如何守护激素健康与生育力｜Shanna Swan 博士

安德鲁·休伯曼：欢迎收听 Huberman Lab 播客。我们在这里讨论科学以及以科学为基础的日常生活工具。我是安德鲁·休伯曼，任教于斯坦福大学医学院，研究领域是神经生物学和眼科学。今天的嘉宾是 Shanna Swan 博士。Swan 博士是西奈山医学院环境医学与公共卫生教授，也是研究各种食物和环境中的毒素与化合物如何影响生殖健康的世界级专家。她关注的是：空气、食物供应、水供应、化妆品，甚至家居用品中的这些化合物，如何从生殖生物学层面影响发育中的胎儿、儿童和成年人，例如影响睾酮、雌激素，以及大脑和身体中受睾酮与雌激素影响的通路；同时也关注环境中的一切事物，以及我们摄入体内的物质，如何影响我们每天的健康和长期健康。今天的讨论会告诉你，为什么生育率确实在逐年大幅下降，而且这种下降已经持续了相当长时间；你还会了解到睾酮水平为何下降、精子数量为何下降、女性多囊卵巢综合征为何增加，以及我们能做些什么。事实上，在今天的大部分讨论中，Swan 博士都会强调一些你每天都能做、而且最终证明非常简单的事情。这些做法包括应该做什么、应该避免什么，以限制你接触这些环境毒素及其影响。因此，到本期结束时，你不仅会从这位研究内分泌干扰物和环境毒素的世界级专家那里获得充分信息，也会充分了解如何获得主动权，如何针对这些化合物掌控自己的健康。在开始之前，我想强调，这档播客与我在斯坦福的教学和研究工作彼此独立。不过，它确实属于我的愿望和努力的一部分：向公众提供免费的科学及科学相关工具信息。秉持这一理念，我要感谢本期播客的赞助商。第一家赞助商是 LMNT。LMNT 是一种电解质饮料，包含你需要的一切，不包含你不需要的东西。也就是说，它按适当比例含有电解质、钠、镁和钾，但不含糖。我们都应该知道，充分补水对于大脑和身体的最佳功能至关重要。事实上，即使只是轻度脱水，也会在相当程度上降低你的认知和身体表现。重要的不只是补水，还要摄入足量且比例合适的电解质。将一包 LMNT 溶解在水中饮用，可以很容易地确保你摄入足够的水分和电解质。为了保证两者摄入适当，我早上醒来时会把一包 LMNT 溶解在大约 16 到 32 盎司水中，基本上起床后第一件事就是喝掉。我做任何类型的体育锻炼时也会喝一包溶于水的 LMNT，尤其是在炎热天气大量出汗、流失水分和电解质时。LMNT 有许多口味很棒的产品。现在我们进入冬季，至少北半球是这样，LMNT 的 Chocolate Medley 口味已经重新上市。我很喜欢这些巧克力口味，尤其喜欢把 Chocolate Mint 混入热水中饮用。当然，即使外面更冷，补水仍然极其重要。事实上，很多人没有意识到，即使天气寒冷，也很容易脱水，因为空气干燥；所以即使你没有注意到皮肤上积累的汗水，你仍然可能流失大量水分和电解质。如果你想试试 LMNT，可以访问 drinklmnt.com/huberman，购买任意 LMNT 冲饮粉后领取 LMNT 试饮装。再说一次，是 Drink LMNT，拼作 L-M-N-T。访问 drinklmnt.com/huberman 即可领取免费试饮装。本期节目还由 ROKA 赞助。ROKA 制造质量极高的眼镜和太阳镜。我多年来一直佩戴 ROKA 的阅读眼镜和太阳镜，非常喜欢。它们重量轻、光学性能出色，而且有很多镜框可供选择。我很高兴地告诉大家，ROKA 与我合作推出了一种新款红色镜片眼镜。这种红色镜片眼镜适合在太阳下山后的晚上佩戴。它们可以滤除来自屏幕和 LED 灯的短波长光，也就是如今最常见的顶灯和普通灯具所使用的 LED 灯发出的光。我想强调，ROKA 红色镜片眼镜不是传统的蓝光阻隔眼镜。它们不是设计用来白天佩戴、滤除屏幕光中的蓝光，而是用来阻挡会在夜间抑制褪黑素分泌、从而改变睡眠的完整波长范围。因此，佩戴 ROKA 红色镜片眼镜有助于让你平静下来，改善入睡过渡。大多数晚上我会熬到大约晚上 10 点，甚至午夜，并在早上 5 点到 7 点之间醒来，具体取决于入睡时间。现在我一到外面天黑就戴上 ROKA 红色镜片眼镜。我注意到自己更容易过渡到睡眠状态，这与我们对滤除短波长光如何让大脑正常运作的全部认识相符。坦率地说，ROKA 红色镜片眼镜看起来也很酷。你可以戴着它们外出吃饭、去听音乐会，或者和朋友一起出门。所以事实证明，支持自己的生物学机制、以科学为依据，同时仍然保持社交生活，确实可以兼得。如果你想试试 ROKA，可以访问 roka.com，也就是 R-O-K-A.com，并输入代码 Huberman，首次下单可节省 20%。再说一次，访问 R-O-K-A.com，在结账时输入代码 Huberman。本期节目还由 BetterHelp 赞助。BetterHelp 提供由持证治疗师完全在线进行的专业心理治疗。我每周接受心理治疗已经超过 30 年。事实上，我认为定期接受心理治疗与定期运动同样重要，其中包括有氧运动和抗阻训练，当然我每周也都会做这些运动。优秀的心理治疗基本上能提供三件事。第一，它能让你与一个真正值得信任、可以谈论所有困扰你的问题的人建立良好关系。第二，优秀的治疗能提供支持，包括情感支持，以及有方向的指导，也就是应该做什么和不应该做什么。第三，专业治疗可以帮助你获得原本不会获得的有用洞见。BetterHelp 让你很容易找到一位你真正有共鸣的专业治疗师，并获得我刚才描述的这三项益处。此外，由于 BetterHelp 完全在线进行，它非常节省时间，也容易安排进繁忙的日程，不需要通勤去治疗师的办公室，不用坐在候诊室，也不用寻找停车位。如果你想试试 BetterHelp，可以访问 betterhelp.com/huberman，首月可享受 10% 折扣。再说一次，是 betterhelp.com/huberman。现在开始我与 Swan 博士的对话。Swan 博士，欢迎你。

Shanna Swan 博士：安德鲁·休伯曼博士，谢谢。

安德鲁·休伯曼：我对今天的谈话感到非常兴奋。我关注你的研究已经很多年，也看过你在其他播客中的一些访谈。我们都在哥本哈根时，我还去听过你演讲。当时我在观众席里，你并不知道我在那里。不过，你作为研究者、公共教育者和作者所做的工作非常出色。我们先从一个基本问题开始：我们所处的环境，包括食物，是否正在损害我们的生殖健康和整体健康？如果是，哪些因素是你会重点考虑的？也许你可以提到一些多年来观察到的最突出的、甚至可能令人震惊但确实重要的结果。过去几十年里，究竟是什么结果，或者哪些结果，真正让你把注意力集中到这里？我还想说说我们在开麦克风前谈到的一点：你是一个怀疑论者。你并不是那种走出门就到处寻找可能扰乱我们生物学、损害我们健康的事物的人，但你确实发现了一些。所以，如果你能和我们分享你观察到的情况，以及你认为对人们来说真正有说服力、重要且值得了解的内容，我们就从这里展开。

Shanna Swan 博士：问题太多了。我大概可以就这个话题讲很久。

安德鲁·休伯曼：请便。在你讲完之前我不会说话。

Shanna Swan 博士：不，不过我想把它拆开来。我们拆开来说。我想第一个问题是：环境中是否存在能够影响生殖健康的力量、化学物质或其他因素？有，对吧？好，我的答案是肯定的。我认为这一点毫无疑问。问题在于何时、对谁，以及剂量是多少，等等。但如果宽泛地说，是否存在这些东西？当然存在。我关注的类别是人造的，主要是人造化学物质。当然，我也会纳入其他因素的影响，例如个人选择，包括睡眠、运动之类。我们可以谈谈这些。不过这里先聚焦于化学物质，因为我认为这正是促使我开展大量研究并写下那本书的原因。我的论点是，环境中的化学物质是一个非常宽泛的类别，因此我们必须说：环境中的某些化学物质，在适当的时间作用于适当的生物体，会影响生育力。好，我还要说明，生育力只是我关注的一个领域；实际上，我主要感兴趣的这类化学物质，是那些会影响身体激素的物质。它们被称为激素干扰化学物质，或内分泌干扰化学物质，也可以叫改变激素的化学物质，名称很多。但这样聚焦有助于你确定应该在哪里寻找影响，因为如果一种物质会改变激素，你就可以提出具体问题：这是某种化学物质，它会影响某种激素吗？是哪种激素？什么时候影响？通过什么方式影响？这几乎已经是在设计实验了，对吧？所以我认为，把重点放在内分泌干扰化学物质上是有用的。

安德鲁·休伯曼：完全同意。

Shanna Swan 博士：是的。

安德鲁·休伯曼：我想，今天我们要谈的大部分内容，可能都会围绕雌激素和睾酮通路展开，涉及大脑和身体的男性化或女性化——

Shanna Swan 博士：对。

安德鲁·休伯曼：……以及精子和卵子的——

Shanna Swan 博士：对。

安德鲁·休伯曼：……质量。

Shanna Swan 博士：对。

安德鲁·休伯曼：……质量。

Shanna Swan 博士：我是一名生殖流行病学家。我是通过一条间接路径走到这个领域的。我认为，最直接把我带到这里的，可能是我对口服避孕药的研究，而口服避孕药就是内分泌干扰化学物质。

安德鲁·休伯曼：它们的设计目的就是如此。

Shanna Swan 博士：对。它们的设计目的就是改变你身体里的激素，也就是你的生殖激素。有意思的是，很久以前我曾在 Kaiser 参与一项关于口服避孕药的研究。那实际上是世界上同类研究中规模最大的一项，目的是弄清口服避孕药是否会产生不良影响；如果会，对谁、在什么时候、以多大剂量产生影响，等等。这是一项非常出色的研究。后来，我在加利福尼亚州卫生服务部工作时，花了相当长时间研究环境化学物质，而不是药物。之后我经历了一个恍然大悟的时刻：我和朋友 John Brock 一起飞往日本，他是 CDC 的化学家，也是一位非常优秀的化学家。长途飞行中我们聊了各种事情，他对我说：“Shanna，你应该研究邻苯二甲酸盐。”我问：“为什么要研究邻苯二甲酸盐？”我以前从没听说过邻苯二甲酸盐，对吧？他说：“现在 CDC 已经能够测量它们了，我们发现每个人体内都有。育龄女性体内有，这是第一点。第二点，NTP 的同事已经展示了一种他们称为‘邻苯二甲酸盐综合征’的现象。”然后他向我解释了这一点。

安德鲁·休伯曼：NTP 是什么？

Shanna Swan 博士：国家毒理学计划，抱歉——

安德鲁·休伯曼：谢谢。

Shanna Swan 博士：……我刚才用了太多字母缩写。

安德鲁·休伯曼：没关系。

Shanna Swan 博士：国家毒理学计划是一个政府研究中心。他们的工作是研究化学物质，了解它们具有什么毒性。可能是生殖毒性，也可能是致癌性或神经毒性，这就是他们的工作。他们已经指出，这些邻苯二甲酸盐具有生殖毒性，尤其针对男性，尤其是在宫内暴露发生时。

安德鲁·休伯曼：孕妇接触了邻苯二甲酸盐，然后胎儿不知怎么就受到了干扰。

Shanna Swan 博士：是的。

安德鲁·休伯曼：如果你不介意，我想知道：母亲是通过食物摄入邻苯二甲酸盐的吗？是吸入的吗？还是落在皮肤上？假设它穿过胎盘屏障进入胎儿，并影响胎儿发育，那么这些物质进入母亲身体的途径是什么？

Dr. Shanna Swan: Right. So in 那些 experiments, it was 通过 food. 但 我们 are exposed in all 那些 ways 你 mentioned. Every way 那 something 可以 get 进入 我们的 身体, phthalates get in there. 但 let's come back to 那. Let me go to the experiment at NTP. So what they did at NTP, National Toxicology Program, they fed mother rats various doses of 这些 various phthalates. 和 what they found was no changes in the females, 或 not 那 they found at 那 time.

安德鲁·休伯曼： The female offspring?

Dr. Shanna Swan: Female offspring, sorry.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 但 in the male offspring, they found 那 the genitals were, I 会 summarize it by saying incompletely masculinized. So I'll explain what 那 is. So 对于 那, I have to back up 和 say something 你 probably know 非常 well, 但 I'll just explain it. The genital tract initially is a ridge. It's a single ridge. It's the same in males 和 females. It's not sexually dimorphic at the beginning. 和 then under the influence of testosterone, in a 非常 具体的 window called the male programming window, in rats it's 天, I think, nine to 12 of gestation. So a 非常 short window.

安德鲁·休伯曼： To orient 人们, I think rat, mouse gestation is 关于 21 天 或 so?

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: So 对于 us, it'll be early 首先 trimester.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Okay. 但 那 comes later. So at 那 time, if they feed the mother 那 chemical in her food, then her male offspring are born 与 changes in his genitals, 或 更多 可能 to, right? 和 so what they tend to have is a smaller penis, 更少 descent of the testes, 更多 可能 to have undescended testicles. There are internal changes 那 我们 didn't get 进入 in 我们的 human 研究 因为 我们 可以't look there, 但 the epididymis, there are changes 和 so on. The whole genital tract is altered. 和 the most 重要 measure 对于 me, as it turned out, 和 对于 humans, 和 perhaps 对于 animals, is something 那 the animal scientists had studied 对于 a long time, 对于 actually 90 plus years, 但 had 从不 been studied in humans. 和 那 is the distance 从 the anus to the genitals. 这 collection of changes in the male genitals was given the name the phthalate syndrome. Now, 你're a physician, 和 I challenge 你 to think of any syndrome aside 从 alcohol, there're fetal alcohol syndrome, of course, there's a syndrome, 但 note what syndrome is attached to a chemical class.

安德鲁·休伯曼： Just 对于 technical purposes, I'm a PhD, not a clinician, 但-

Dr. Shanna Swan: Okay, sorry.

安德鲁·休伯曼： 但 I worked on neural development 对于 many years-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... 和 then prior to 那, some endocrine stuff.

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： So I'm facile 与 the general terms.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 一 那 comes to 心智 会 be, 对于 instance, the thalidomide babies, right? A anti-miscarriage drug 那 changed limb development. 那's a 非常 extreme example. I 会 say in human normal development, what I'm most familiar 与 are the early organizing effects of androgens 那 convert to estrogen on external phenotype, which is basically nerd speak 对于 期间 development, the Y chromosome leads to the production of a number of genes 和 eventually proteins 通过 RNA, et cetera, including testosterone 和 dihydrotestosterone, 那 in the 大脑 organizes the 大脑 male 和 causes the growth of the penis. 或 organizes, meaning it sets up the penis-

Dr. Shanna Swan: Yeah. Right

安德鲁·休伯曼： ... to then 期间 puberty when the penis is exposed to testosterone 和 estrogen 和 DHT-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... it's a bunch of things, not just testosterone, the penis grows.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： So 那-

Dr. Shanna Swan: 和 lots of other things.

安德鲁·休伯曼： Right, lots of other things. So the word soup 那 I just-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... put forward is basically saying 那 there are a lot of things in development where 激素 set up a potential to respond to other 激素 later.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： It's not 那 testosterone grows the penis 期间 development. It does 那, 但 更多 so it establishes a potential 对于 the penis to grow when exposed to things later 期间 puberty. Do I have 那 right?

Dr. Shanna Swan: Right. As far as the name goes, which is the phthalate syndrome, there is thalidomide. It's not usually called a thalidomide syndrome, 但 it could be.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: So 你're right 关于 那. 但 it's extremely rare, 和 there is no chemical in the environment, as opposed to a pharmaceutical, 那 is given a syndrome. So 这 is 非常, 非常 unique. 和 so I thought Wow. John's telling me 这 on the plane, right?

安德鲁·休伯曼： Something in the environment 那 is basically having an endocrine 和 身体 disruptive effect, at least on par 与 fetal alcohol syndrome-

Dr. Shanna Swan: Right. Exactly

安德鲁·休伯曼： ... 和 thalidomide syndrome.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: Well, at 这 point, it was only animals, right? 因为 John was telling me 关于 the NTP 研究, which was in rats. 和 so I thought, wow. I like puzzles, so my 首先 question was, is 这 happening in humans? 你 可能 ask 那. It's a natural thing to ask.

安德鲁·休伯曼： Great question.

Dr. Shanna Swan: 和 then I thought, how 会 我们 find out? 和 answering 那 question took me 10 years. Okay. 和 so if 你 think 关于, okay, phthalate in the mother, changes in the genitals of the offspring, connect them. How do 我们 do 那? Right? So 我们 have to start 与 phthalates in the mother. So how do 我们 know 那? Well, fortunately 或 not, I had stored a lot of urine 从 pregnant women 从 a 研究 那 I was doing on sperm count. I just got the women's urine coincidentally, if 你 会. I just thought, well, save it. It's not expensive 和 not hard. Minus 80-degree freezers, doesn't take a lot of room, put it in there. So I had 这 urine saved 从 pregnant women, 和 then I knew 从 John 那 我们 could look in the urine 对于 phthalate metabolites. So 这些 are products 那 the 身体 forms when they're exposed to phthalates, 和 你 可以 measure them in urine. So I thought, okay, I could get 那 urine, I could look at the phthalate metabolites, 和 then I'd know what the mother was exposed to. 和 based on the animal 数据, 我们 have good 证据 那 it actually makes its way to the fetus. So then I thought, okay, then maybe there's a change in the babies. So then I had to get the babies. So fortunately, I had done 这 研究 on pregnant couples, pregnant women 和 their partners, 和 I was able to call them 和 say, "会 你 come in 和 let us measure 你的 babies' genitals?" Right? 和-

安德鲁·休伯曼： How willing were parents to let 你 do 那? 那 seems-

Dr. Shanna Swan: They were okay. Most of them were okay 与 那.

安德鲁·休伯曼： Were they?

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yeah. Mm-hmm.

Dr. Shanna Swan: Well, they trusted us. They had been-

安德鲁·休伯曼： Sure

Dr. Shanna Swan: ... in a 研究 与 us, 和 我们 were reputable.

安德鲁·休伯曼： 那些 babies were still-

Dr. Shanna Swan: Young

安德鲁·休伯曼： ... yeah

Dr. Shanna Swan: ... 但 not newborns.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: So 这 was a while later. The babies 那 我们 actually got were, on average, I think 关于 12 months old.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: So not ideal maybe 因为 the rats had been measured at birth, the rat genitals had been, 但 那's what 我们 could do at 那 time.

安德鲁·休伯曼： Yeah, the reason I ask is there's 总是 the potential 对于 ongoing phthalate exposure-

Dr. Shanna Swan: Sure

安德鲁·休伯曼： ... to the newborn.

Dr. Shanna Swan: Absolutely.

安德鲁·休伯曼： 但 I suppose in either case, 你're able to draw some potential link between, 或 potentially draw a link, I have to be careful 与 my language there, between phthalate exposure in utero 和 ex utero 和 这些 external biomarkers.

Dr. Shanna Swan: Yeah. Given 那 the critical window is quite short 和 quite early-- By the way, let me just say, when the rats, they did a lot of work on 这 critical window, 和 when the rat moms were exposed 之前 天 nine, it did nothing. 和 when they were exposed 之后 天 12, it did nothing. So it was only the exposure 期间 那 critical window is 非常 delicate, 和 it's, by the way, true of the 大脑 as well. So teasing out what is the critical window is 一 of the challenges 那 我们 have when 我们 work 与 这些 chemicals. So I wasn't so much worried 关于 exposure in the delivery room 和 in their feed as in the 首先 year of life 因为 I knew 那 it was unlikely to change 这些 measures.

安德鲁·休伯曼： Mm-hmm. 非常 重要 point.

Dr. Shanna Swan: Do other things-

安德鲁·休伯曼： Yeah

Dr. Shanna Swan: ... maybe, 但 not 这些 measures. So then the question became what 你 were asking is, what do 我们 measure? What do 我们 actually measure? 和 if 你 think 关于 a newborn rat 或 mouse, their genitals are pretty small. 和 it's 非常 difficult to know exactly how 那 corresponds to the human genital 系统 和 what 你 see at birth-

安德鲁·休伯曼： 不同的 enough animal, yeah. Mm-hmm

Dr. Shanna Swan: ... when 你 spread a boy's legs, right? 和 so I got a pediatrician in Los Angeles who worked 与 me on how to make 那 translation 和 how to do 这 exam. 和 那 took us quite a while 因为 我们 确实 wanted to come as close as 我们 could. What was clear was 那 the anus part of it was easy. 你 go to the center of the anus, so 那 was easy. Then what's the other landmark? What's the genital landmark? So it turns out there are in males, 二, 和 in females, there are 二 as well. 但 let's just talk 关于 males. So 对于 males, the best place to measure, 和 actually closest to the rat measurement, is the place where the 组织 changes, where the scrotum inserts. 和 那 goes 从 rugated to smooth 组织, 和 at 那 point, it's pretty clear, pretty easy to measure. 和 那 was the anoscrotal distance. 和 the other measurement 我们 took was the anopenile distance, 和 那 was the anterior insertion of the penis.

安德鲁·休伯曼： The part closest to the 身体.

Dr. Shanna Swan: The closest to the head. Yeah.

安德鲁·休伯曼： Closest to the head.

Dr. Shanna Swan: Yeah. 和 那 was not so obvious 因为 你 don't have a change in 组织 there. So where exactly do 你 put 你的 caliper? 和 我们 had a lot of discussion 关于, do 你 press down? Do 你 what? Where exactly do 你 make 那 mark? 和 actually, the anoscronal is the measurement 与 the least variance 因为 你 可以 measure it most precisely.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 但 the anopenal is another measurement. 和 then 你 可以 do something 相似的 in females 和 我们 did 那, 但 我们 maybe don't have to go 进入 那 now. So 我们 designed 这 exam, 和 我们 did a lot of work to make sure it was repeatable across examiners. 和 what 我们 finally did was bring the mothers in, bring the babies in, 和 got 三 measurements. 和 then on every 10th baby, 我们 got an independent examiner to get 三 measurements, so 我们 could look at within 和 between examiner variation. 你 understand 这 is the 首先 time 这 had been done 这 way in humans. There was a Mexican 研究 那 tried to do 这, 和 I 从不 learned 非常 much 关于 it. 和 I was excited 那 they had done 这, 但 I'm not sure how it relates to 这. So I just mention 那 out of honesty. Somebody in Mexico did 这. 但 to my knowledge, 这 is the 首先 time it was used as a toxicological measure in humans.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: So 我们 did 那 研究. 我们 related 那些 measurements to what CDC had measured in the urine of 我们的 women, collected while they were pregnant, 和 我们 found the phthalate syndrome.

安德鲁·休伯曼： Could 你 explain what the correlation was between phthalate metabolite 水平, which is, I believe-

Dr. Shanna Swan: Not by number 因为 I don't remember it anymore.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: 但 there was a significant-- Let's just take the AGD. The AGD of mothers who had higher 水平 of 三, the most anti-androgenic phthalates, I'll tell 你 what 那些 are in a 分钟, had significantly shorter anogenital distance. 和 then I have to say 那, which I haven't said 和 应该 have, 那 anogenital distance is sexually dimorphic. So it tends to be 50% to 100% longer in males than females. 那 makes sense if 你 think 关于 what's going in 那 space. There's a lot of real estate

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... in males between the anus 和 let's say the penis, penile insertion, much 更多 than in females. So it's natural 那 那 会 be longer. I began doing some work looking at other species, 和 it turns out 那 那's true in all mammalian species except 二.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 一 is the hyena.

安德鲁·休伯曼： Oh, right.

Dr. Shanna Swan: 和 一 is the elephant. So in the hyena, I'm just saying 这 因为 你 会 be amused by it, I think.

安德鲁·休伯曼： Well, I-

Dr. Shanna Swan: 你 know 关于 hyenas?

安德鲁·休伯曼： I do. I know 更多 关于 hyena genitalia than I'd like to admit. 和 I 可以 tell 你 why 之后 你 educate us, 但 I'll keep my explanation brief. 但 I'm 非常 familiar 与 hyena genitalia.

Dr. Shanna Swan: So I know Steven Glickman. 你 可能 know him, too. He works in Berkeley 与-

安德鲁·休伯曼： Yeah, he was my instructor when I was a graduate student at Cal.

Dr. Shanna Swan: Oh my gosh.

安德鲁·休伯曼： 和 I used to run in Tilden Park, I suppose I'll tell it now, 和 there was a colony of wild hyenas.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 但 they were behind chain link.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： It's actually a favorite hike of mine up the Strawberry Canyon Trail.

Dr. Shanna Swan: Yeah. I did 那 trail.

安德鲁·休伯曼： A good friend of mine, Brian Prendergast, who's now a professor at the University of Chicago, worked on the prairie voles 那 were also housed at 那 facility.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 和 a fun thing to do was to go see the hyenas 与 Steve. They're brutally dangerous animals. 和 Steve has tons of stories 关于 them. 我们 应该 probably resist 我们的 temptation to-

Dr. Shanna Swan: Go 进入 it.

安德鲁·休伯曼： ... spiral 进入 那. Maybe sometime I'll do a little 晚上 chat podcast where I tell Steve Glickman stories. He's a delightful person. 和 yeah, let's just say 这, the female hyenas have clitorises larger than some of the male hyena penises, 和 那些 females give birth 通过 那些 clitorises.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： As 我们 both know.

Dr. Shanna Swan: So 你 会 not be surprised to know 那 the female AGD is longer than the male.

安德鲁·休伯曼： Right. 因为 they're heavily androgenized.

Dr. Shanna Swan: Exactly.

安德鲁·休伯曼： As I recall, by androstenedione as a-

Dr. Shanna Swan: Actually, I don't-

安德鲁·休伯曼： Yeah

Dr. Shanna Swan: ... know 那. 但-

安德鲁·休伯曼： It became popular 期间 the era of steroids in professional baseball 因为 androstenedione was being used pretty frequently in baseball at 那 time. Anyway, 我们 could go down the spiral of-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... hyenas.

Dr. Shanna Swan: 但 also, in terms of behavior, the female is the alpha.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： They eat 首先.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： They're physically 和 hierarchically dominant-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... in hyenas. Yeah.

Dr. Shanna Swan: So it's 确实 interesting, isn't it, 那 they 会 have a longer, 更多 masculine anogenital distance. Elephants, 我们 won't go 进入 now, 但 they're kind of midway in many things, including their 关于 equal-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... anogenital distance in males 和 females. Other than 那, humans 和 other species, male anogenital distance is 50% to 100% longer. 然而, so 三 phthalates, diethylhexyl phthalate, DEHP, dibutyl phthalate-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... DBP, 和 butyl benzyl phthalate, BBzP, are the most anti-androgenic testosterone-lowering phthalates, 和 那些 are the ones 那 were associated 与 a shorter anogenital distance in males.

安德鲁·休伯曼： In human males.

Dr. Shanna Swan: Human males 和 animal. So 我们 replicated 那 animal 研究 in humans. 和 then, 因为 你 know 这 is how it is in science, I had to do it all again. Right? So I started a whole new 研究, 和 那 研究 is still going on. The children are still being followed. I think 我们 started in 2012. The 首先 paper on anogenital distance came out in 2005. Had a pretty big impact.

安德鲁·休伯曼： So 这些 are 研究 where 你're looking at the anogenital distance in relatively newborn humans, then tracking 那 distance.

Dr. Shanna Swan: No, 那's 不同的. Tracking is another 研究.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Okay. 这 is just 二 研究 on demonstrating the Thali syndrome-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... in human males.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Okay. So the 首先 一 I described, the 秒 一, the replication. 和 the 秒 一 is the 一 那's going on still. 和 what it does to their reproductive function, 我们 don't know. The kids are only 12 years old now, so 我们 会 like to know 那, 和 我们 会 know 那. Okay, 但 I have another answer 对于 你 关于 那. So 我们 started the 秒 研究, 和 the 秒 研究, which is called TIDES, which is the Infant Development 和 Environment 研究. By the way, 这些 are both in four cities in the United States. 和 there 我们 did it right. So 我们 got the urine in the 首先, early urine 因为 我们 knew 那 could be 重要. 我们 didn't have 那 option in the 首先 一. Remember, 那些 urine samples were accidental. 我们 got them when 我们 could, right? 和 我们 got repeated urines, 一 in each trimester, to look at the effects in 不同的 trimesters. 和 then 我们 examined the babies at birth, which is what the rats-- So 我们 came much closer to replicating the rodent 研究. 和 我们 saw it again.

安德鲁·休伯曼： I'd like to take a quick break 和 thank 我们的 sponsor, AG1. AG1 is an all-in-一 vitamin mineral probiotic drink 与 adaptogens. I've been taking AG1 daily since 2012, so I'm delighted 那 they're sponsoring 这 podcast. The reason I started taking AG1, 和 the reason I still take AG1 once 和 经常 twice a 天, is 因为 it is the highest quality 和 most complete foundational nutritional supplement. What 那 means is 那 AG1 ensures 那 你're getting all the necessary vitamins, minerals, 和 other micronutrients to form a strong foundation 对于 你的 daily health. AG1 also has probiotics 和 prebiotics 那 support a healthy gut microbiome. 你的 gut microbiome consists of trillions of microorganisms 那 line 你的 digestive tract 和 impact things such as 你的 免疫系统 status, 你的 metabolic health, 你的 激素 health, 和 much 更多. So I've consistently found 那 when I take AG1 daily, my digestion is 改善了, my 免疫系统 is 更多 robust, I rarely get sick, 和 my 情绪 和 mental 专注 are at their best. In fact, if I could take just 一 supplement, 那 supplement 会 be AG1. If 你'd like to try AG1, 你 可以 go to drinkag1.com/huberman to claim a special offer. 对于 这 month only, November 2024, AG1 is giving away 一 free month supply of omega-3 fatty acids 从 fish oil, in addition to the usual welcome kit of five free travel packs 和 a year's supply of vitamin D3 K2 与 你的 order. Omega-3 fatty acids are critical 对于 大脑 health, 情绪, cognition, 和 much 更多. Again, go to drinkag1.com/huberman to claim 这 special offer. 更多 phthalate exposure equates to shorter anogenital distance in males. It was approaching the distribution in females. It sounds like the distributions moved 更多 closely together.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: Yes. 尽管 it wasn't the females 那 moved.

安德鲁·休伯曼： Sorry. The male distribution-

Dr. Shanna Swan: Became 更多 like the female

安德鲁·休伯曼： ... became 更多-

Dr. Shanna Swan: Right. Feminized

安德鲁·休伯曼： ... I was going to say feminized, 但 更多 female-like in its-

Dr. Shanna Swan: Yeah. 但 这些 boys also had smaller penises, 更少 descent of the testes, smaller scrotums. So they were smaller. Everything was in their genital areas.

安德鲁·休伯曼： Are all the secondary sex characteristics of puberty in males, Adam's apple, facial hair growth, thickening of the vocal cords, 因此 lowering the voice, et cetera, are 那些 all later activating effects of 激素, 或 are there precursors to 那些 那 are present in males? 因为 in mice, as I recall, I couldn't tell 你, 我们 call it in the laboratory, 人们 总是 chuckle at 这, 但 it's like sexing the animals when 你 look to determine if it's a male 或 female. When they're 确实 young, 你 have to look carefully at 首先, right? 和 then 你 get pretty good at it. As they get older, it gets easier. 但 when the mice are feet down, back up, 你 可以't 确实 tell.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 你 可以't 确实 tell.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： As the mice get older, their testicles become visible in the males-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... even 从 above.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 但 as far as I know, there aren't 确实 external markers. So 你 may have found the 一 truly external biomarker of maleness.

Dr. Shanna Swan: Of maleness. 和 so I do want to say 一 thing 关于 females, 因为 then 那'll lead me to my conclusion 关于 the role of 这 measure. So if the mother is exposed to 更多 testosterone than expected, 你 可能 expect 那 her female offspring 会 have a 更多 male anogenital distance.

安德鲁·休伯曼： Is 那 the case?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： So it's a bidirectional effect.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： 可以 我们 also presume 那 if the mother either secretes 或 is exposed to 更多 androgen, then the males 可以 become hyper-male?

Dr. Shanna Swan: No. I don't know what 那 会 be. 我们 从不 saw anything 那 会 be hyper-male. So the yes I said to 你 was the result of a 研究 where 我们 looked at the girls born to women 与 PCOS. So women 与 PCOS, as 你 know, have excess testosterone.

安德鲁·休伯曼： Polycystic ovarian-

Dr. Shanna Swan: Cystic. Oh, sorry.

安德鲁·休伯曼： Polycystic ovarian syndrome. No, 那's okay. 我们've talked 关于 it a little bit 之前 on the podcast.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： My understanding is it's associated 与 elevated 水平 of androgens.

Dr. Shanna Swan: Mm-hmm 那's right.

安德鲁·休伯曼： In females. Yeah

Dr. Shanna Swan: 和 women 经常 have facial hair 和 你 know.

安德鲁·休伯曼： Not just the moms, 但 the 人们, the women 与 PCOS-

Dr. Shanna Swan: Yes

安德鲁·休伯曼： ... have elevated androgens.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： 我们're not talking 关于 pregnant moms anymore.

Dr. Shanna Swan: Exactly.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: 和 so in 我们的 研究 population, 我们 did a search 对于 women who had diagnoses of PCOS 和 took 那 as a marker of higher testosterone exposure 和 then looked at the girls, 和 yes, 那些 girls had a longer, quote, "更多 masculine anogenital distance."

安德鲁·休伯曼： What age group were 你 looking at 与 PCOS?

Dr. Shanna Swan: In the infants. Oh, the PCOS was at pregnancy, at the time they were pregnant 或 之前.

安德鲁·休伯曼： So presumably 人们 between somewhere in their 20s out to their 40s.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： So adult human females who have PCOS, 我们 know they have higher 水平 of androgens, 但 they also have 更多 male-like anogenital distance.

Dr. Shanna Swan: They do not. Their daughters do.

安德鲁·休伯曼： Their daughters do. Thank 你 对于 那 clarification.

Dr. Shanna Swan: Yes. Their daughters. 和 so put 这 together, 这 measure is a look inside the womb at the androgen 水平 那 the fetus is exposed to at 那 time, which is amazing 因为 你 可以't go in there 没有 disturbing-- 你 可以't. 和 so 这 is 非常 early 首先 trimester. 你 可以't even get fluid 和 so on. So 这 tells 你, 这 is like a readout-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... of what was in the fluid at the time. So then 你的 next question was, what does 这 mean 对于 later fertility? Yes?

安德鲁·休伯曼： Yeah. What is the impact of 这 early androgen exposure 进入 female offspring, 或 let's just say reduction in functional androgen exposure to male offspring? The reason I'm using 这 loop-de-loop language is, as 你 probably know, 但 对于 the audience, not trying to complicate things here, 但 a lot of the masculinizing effects of 激素 in fetal development is actually testosterone 那's converted 进入 estrogen, so it 可以 get pretty tricky.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 但 maybe 对于 sake of simplicity today, 我们'll just stick 与 androgen effects on masculinization, 与 the understanding 那 some of 那些 effects-

Dr. Shanna Swan: Are higher

安德鲁·休伯曼： ... are the consequence of testosterone being converted 进入 estrogen.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： It's just 那 人们 form such strong associations falsely 那 testosterone is-

Dr. Shanna Swan: Male

安德鲁·休伯曼： ... maleness, 和 那's not true, 和 estrogen is femaleness 和 it just gets 确实 murky. 但 对于 the time being, 你 identified an external biomarker of fetal androgen, AKA masculinization via the mother.

Dr. Shanna Swan: 那's right.

安德鲁·休伯曼： Got it.

Dr. Shanna Swan: Okay. So then 我们 asked the question 你've asked 和 many 人们 asked, who cares? Why 会 我们 worry 关于 a boy having a slightly smaller anogenital distance?

安德鲁·休伯曼： Well, I 可以 tell 你 there are many boys 那 are probably worried 关于 it right now.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： They probably got the ruler 和 the calipers out right now.

Dr. Shanna Swan: 但 I'm going to answer 那 question.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: So I told 你 那 我们的 kids are too young. They're not producing sperm right now. So 我们 had to go to an adult population. 和 so 我们 went to a population of college students in Rochester, New York. 和 what 我们 did there was make an assumption, which is based on animal 数据. It's true in animals. 我们've been following the animal path here all along. So in the animals, my colleague, Earl Gray, who did 这些 研究, said-

安德鲁·休伯曼： His name is Earl Gray?

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 那's cool.

Dr. Shanna Swan: Yeah. He said, "AGD is forever."

安德鲁·休伯曼： Anogenital distance is forever.

Dr. Shanna Swan: Now, what 那 means is it's not like 你的 anogenital distance today is what it was when 你 were born. Of course, 你're a bigger person, 但 那 means adjusted 对于 身体 size. So if 你 assume 那 AGD is forever, if 你're born 与 a short-对于-你的-size AGD, then when 你're 20, 你'll have a short-对于-你的-size AGD. Okay? 可以 我们 assume 那?

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Okay. So if 我们 assume 那, then if 我们 get 这些 college students to come in 和 我们 可以 measure their anogenital distance, 我们're getting a reflection of what it was when they were born. Okay? 和 then 我们 可以 get their sperm count, 和 then 我们 可以 see if they're related, 和 那's what 我们 did. So 我们 got 这 population of volunteers, paid them $75, 和 一 of the guys said, "对于 75 bucks, 你 可以 do anything." 和 so what 我们 did was 我们 measured their anogenital distance, 和 then 我们 got them to give a semen sample 和 complete a questionnaire, 和 things 你 do in a 研究.

安德鲁·休伯曼： 我们'll link to 那 研究, 但 I have a couple questions-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 关于 the controls in 那 研究, just 对于 sake of 人们 understanding how a 研究 like 这-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 会 be done.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： I don't expect 你 to recall all the details, 但 你're adjusting 对于 身体 size 和 身体 weight.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Height, weight-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... what are the factors 那 会 scale here 那 会 allow 你 to normalize-- In other words, what 你're trying to do is backtrack to what it 可能 was at infancy.

Dr. Shanna Swan: No, 我们 didn't actually try to go back.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Let me just tell 你 what the 结果 were.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: In 这 group of men, if they had a longer anogenital distance, they had a higher sperm count

安德鲁·休伯曼： Got it. So 你 会 correlate 那些 二 measures.

Dr. Shanna Swan: Right. 和 then if 我们 wanted to say something 关于-- 我们 didn't try to say anything 关于 how it was when they were born. 我们 just said, okay, 我们'll take 那 assumption 那 这 reflects their early AGD.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: If 我们 want to say something 关于 early AGD 和 sperm count. So it's easy to say AGD is related to sperm count 因为 我们 measured 那. 我们 saw 那. A correlation, 那's published. Okay. If 我们 want to say their early AGD at birth 和 their sperm count, 那's a leap of faith in some sense-

安德鲁·休伯曼： Right

Dr. Shanna Swan: ... 因为 我们 don't have their early.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 对于 这些 guys in Rochester, 我们 didn't measure their AGD at birth. So-

安德鲁·休伯曼： Were there any conditions of being a participant in the 研究 such as refraining 从 alcohol, cannabis, et cetera, in the 90 天 prior?

Dr. Shanna Swan: No.

安德鲁·休伯曼： Ninety 天 being the-

Dr. Shanna Swan: No, I don't think so

安德鲁·休伯曼： ... duration of spermatogenesis.

Dr. Shanna Swan: I don't-- Yeah.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: I don't remember 那.

安德鲁·休伯曼： 这些 are college students-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... so presumably some of them are drink-- Okay.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： So, 但 in the end, it was a robust-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... a robust link.

Dr. Shanna Swan: 和 then, Mike Eisenberg, who 你 可能 know at Stanford.

安德鲁·休伯曼： Yeah, my colleague at Stanford. He's been on 这 podcast.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yep.

Dr. Shanna Swan: Oh, good.

安德鲁·休伯曼： Yep.

Dr. Shanna Swan: So he's a colleague of mine, too. 和 he looked at men in a fertility clinic, 和 那些 who had borne children 和 那些 who had not borne children. 和 the men who had borne children had a longer anogenital distance than men who had 从不 borne a child.

安德鲁·休伯曼： 从不 borne, 但 were trying.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： 这些 were not 人们 who opted out.

Dr. Shanna Swan: Yes. Right.

安德鲁·休伯曼： 这些 were-

Dr. Shanna Swan: Exactly.

安德鲁·休伯曼： 这些 were 人们 who were-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... having challenges 与 fertility-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... versus success 与-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... fertility.

Dr. Shanna Swan: 和 by the way, the question of how 你 measure AGD in an adult man is a 不同的 question than how 你 measure it in a newborn. 和 我们 did a lot of work on 那, 和 Mike 会 help 与 那, too.

安德鲁·休伯曼： So it sounds like-- Oh, 和 may I ask, were the sperm counts 那 were on the, let's just say the lower quartile. Were the, quote-unquote, "lower sperm counts," functionally lower? 因为 I 总是 wonder 关于 这. It's come up in a number of discussions 与 Robert Sapolsky, 与 Mike Eisenberg, 和 now I'm asking 你. When 我们 hear 那 sperm counts are going down, are they going down to the point where fertility is impacted? 那's 确实 the-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 一 of the, I think, functional questions.

Dr. Shanna Swan: So let's lay aside the question of AGD, right? 因为 那's 确实 interesting, 但 let's talk 关于 sperm count. Okay.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Okay. There's a beautiful 研究 among pregnancy planners out of Denmark, quite a long time ago. 和 in 那 研究, what they did was take couples 那 were trying to conceive 那 had 从不, 或 not recently, I 可以't remember, used oral contraceptives. 和 then they saw what the sperm count was 和 how long it took them to conceive, right? Time to pregnancy in relation to sperm. 和 what they showed is a 确实 interesting curve, which has 从不 been corrected, to my knowledge. It's what I use 和 what I think 人们 use. Which is 那 if 你-- I wish I could draw it here. I wish 我们 had a bl-- 你 应该 have a board, a whiteboard here.

安德鲁·休伯曼： The problem is a lot of 人们 are listening. 但 maybe 我们-

Dr. Shanna Swan: Yeah, I know

安德鲁·休伯曼： ... 我们 可以 talk 人们 通过 it.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Sorry.

Dr. Shanna Swan: So just think 关于 a curve where 你 go all the way down to zero. 那 会 be no sperm. 和 then as the probability of conceiving is zero, so 你're looking at sperm count along the x-axis 和 months to conception.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 what 你 see is 那 if 你 have no sperm, 你 have no conception. If 你 go up to 大约 40, 45, there's a steep 增加. So the 更多 sperm 你 have-

安德鲁·休伯曼： Forty, forty-five million?

Dr. Shanna Swan: Million per milliliter.

安德鲁·休伯曼： 和 这 is million per milliliter, so just pure concentration, not number of motile sperm. 这 is just-

Dr. Shanna Swan: 那's it. Correct

安德鲁·休伯曼： ... how many sperm. 我们're not talking 关于 quality-

Dr. Shanna Swan: No

安德鲁·休伯曼： ... 我们're just talking 关于 number.

Dr. Shanna Swan: No, just the number.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: 和 when 你 have 45 to 50 million per milliliter, 和 below, it matters a lot what 你的 sperm count is. 人们 say it doesn't matter. Yeah. If 你 get in 这 range where the probability of conception is dropping off 确实 rapidly-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... it matters a lot.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 then 大约 45 to 50, it starts to 水平 off. 和 then 之后 那, certainly 之后 100, probably 75, it doesn't matter at all.

安德鲁·休伯曼： So 100 million sperm per milliliter-

Dr. Shanna Swan: Yes

安德鲁·休伯曼： ... of semen.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: So 可以 你 see 这?

安德鲁·休伯曼： Mm-hmm. Yep.

Dr. Shanna Swan: Okay. So when 人们 say, "Does sperm count matter 对于 fertility?" Yes, it matters a lot if it's low, 和 no, it doesn't matter at all if it's high.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: So 我们 just have too many sperm. I mean, I don't, 但 humans, 你 know. 和 there's-

安德鲁·休伯曼： So nature runs a probability game.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Overproduce sperm.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Some of 那些 会 be high quality, some 会 be low quality-

Dr. Shanna Swan: Exactly

安德鲁·休伯曼： ... depending on their age, 那 is, when they were generated.

Dr. Shanna Swan: 或 their conditions.

安德鲁·休伯曼： 或 their conditions, how much 热 exposure, et cetera.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： So nature runs a probability game.

Dr. Shanna Swan: 那's right.

安德鲁·休伯曼： Hoping 那 the best quality sperm 会 fertilize the egg.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： So below 45,000, excuse me, below 45 million-

Dr. Shanna Swan: Million per milliliter

安德鲁·休伯曼： ... below 45 million sperm per milliliter of semen, the sperm count 确实 matters. It drops off precipitously.

Dr. Shanna Swan: 那's right.

安德鲁·休伯曼： Once 你 get up to 75, 100 million per milliliter of sperm, then-

Dr. Shanna Swan: It's all good.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: 你're good to go.

安德鲁·休伯曼： Right. 和 sperm counts range anywhere 从, it could be low, eight, nine, 10 million per milliliter in the 非常 low situation.

Dr. Shanna Swan: It could be zero.

安德鲁·休伯曼： It could be zero in some 人们, right? All the way up to 400-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... million. There's a huge range.

Dr. Shanna Swan: 那's right.

安德鲁·休伯曼： 和 那's a function of age, it's a function of genetics, it's a function of presumably phthalate exposure. Right?

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： I'd like to take a quick break 和 thank 一 of 我们的 sponsors, Function. I recently became a Function member 之后 searching 对于 the most comprehensive approach to lab testing. While I've long been a fan of 血液 testing, I 确实 wanted to find a 更多 in-depth program 对于 analyzing 血液, urine, 和 saliva to get a full picture of my 心脏 health, my 激素 status, my 免疫系统 regulation, my metabolic function, my vitamin 和 mineral status, 和 other critical areas of my overall health 和 vitality. Function not only provides testing of over 100 biomarkers key to physical 和 心理健康, 但 it also analyzes 这些 结果 和 provides insights 从 top doctors on 你的 结果. 对于 example, in 一 of my 首先 tests 与 Function, I learned 那 I had too high 水平 of mercury in my 血液. 这 was totally surprising to me. I had no idea prior to taking the test. Function not only helped me detect 这, 但 offered medical doctor-informed insights on how to best 减少 那些 mercury 水平, which included limiting my tuna consumption, 因为 I had been eating a lot of tuna, while also making an effort to eat 更多 leafy greens 和 supplementing 与 NAC, N-acetylcysteine, both of which 可以 support glutathione production 和 detoxification, 和 worked to 减少 my mercury 水平. Comprehensive lab testing like 这 is so 重要 对于 health, 和 while I've been doing it 对于 years, I've 总是 found it to be overly complicated 和 expensive. I've been so impressed by Function, both at the 水平 of ease of use, 那 is getting the test done, as well as how comprehensive 和 how actionable the tests are, 那 I recently joined their advisory board, 和 I'm thrilled 那 they're sponsoring the podcast. If 你'd like to try Function, go to functionhealth.com/huberman. Function currently has a wait list of over 250,000 人们, 但 they're offering early access to Huberman Lab listeners. Again, 那's functionhealth.com/huberman to get early access to Function. 我们 were on to the fact 那 sperm counts are dropping. There's a relationship to anogenital distance, 和 there's a relationship between anogenital distance 和 phthalate exposure.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 和 then I asked the question, okay, 我们're hearing 关于 sperm counts dropping, 但 is it functionally relevant? Is 那 一 of the reasons why fertility is dropping? 和 我们've also got the female side where 我们've got women 与 elevated androgens. So 我们 可以 talk 关于 那 a little bit later. 和 then, of course, 我们 have the sociobiology piece where 人们 are opting out, 或 it's also economics in some cases, opting out of having kids.

Dr. Shanna Swan: Right. So let's go back to sperm count, 因为 我们 haven't 确实 talked 关于 那.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: It's a kind of a 不同的 path, 和 my introduction 进入 phthalates was not 通过 sperm count. Right? It was 通过 这 question of my colleague asking me, "你 应该 look at 这," 和 challenged, 和 I looked at it, 和 那 was 确实, 确实 interesting journey 那 I went on. Okay? 但 there was a separate, 对于 a while, journey 那 I was on, 和 那 started in the late 1990s when I was asked to join a committee of the National Academy of Sciences. 和 那 committee was assembled to look at the question of whether hormonally active chemicals, endocrine-disrupting chemicals in the environment posed a threat to human health.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 因为 at 那 time, it was like, well, yeah, 我们 hear 关于 这, 但 应该 我们 care? Right? 和 so 那 committee wanted to consider a 研究 那 had come out of Denmark a few years earlier, which claimed 那 sperm count had dropped 50% in 50 years.

安德鲁·休伯曼： Wow. 那's a huge drop.

Dr. Shanna Swan: 我们're seeing worse than 那, by the way, now. So, okay. They said to me, I was the only statistician on the panel, "会 你 look at 这 和 see if 我们 need to consider 这 in 我们的 deliberations?" 和 as I mentioned, I'm skeptical, 和 I looked at it, 和 I thought, "Eh, I don't think so." 那 was my initial reaction. 和 那 was 因为, 首先 of all, I didn't know who had written 这. I just saw it in a journal, 和 it was not 非常 big 和 not 非常 many figures, not 非常 much 数据, 和 I thought of it, 和 I thought, "那's a big claim 对于 a little paper. 但 I'll look at it, 因为 it's 重要." 和 so what I did then was to think 关于 all the factors 那 我们 epidemiologists call confounders.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Things 那 可能 have caused 那 decline if it wasn't real biologically. Right?

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 so 我们 could think of some of them together. Maybe the method of counting sperm had changed, so 那 later methods counted fewer sperm in the same sample. 那's certainly 可能, right? 但 it turned out 那 wasn't the case 因为 they actually had all used the same method. 和 maybe the men had changed. 你 可以't get a sperm count at random. 你 have to get somebody to volunteer, right? So who were 这些 men? 或 were they 非常 不同的 in the early part of the 研究 和 the late part of the 研究 in a way 那 maybe in the late part of the 研究, there were men 与 lower sperm count, 和 they were 更多 concerned. Maybe they were 更多 obese. 那's pretty plausible. Obesity is related to semen sperm count, fertility. 和 maybe they smoked 更多, 和 so on 和 so forth. Right? So what I did was to get the 61 研究, go 通过 them, 和 try to extract information on all the factors 那 could explain the decline. So I created a multivariable model 和 ran 那 model. 和 to my astonishment, when I was done, the slope of the decline was exactly the same to the 首先 decimal place. It had not explained anything. 和 I was like, "Oh my God, 这 looks like it 可能 be real."

安德鲁·休伯曼： 和 对于 那些 listening, what Dr. Swan is describing is being the excellent scientist 那 she is, she went 和 looked 对于 all the things 那 could impact the result 那 were not related to what the main conclusion seemed to be, which is 那 sperm counts were going down over time.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Right? 和 这 is 确实 重要 因为 I think what 我们're talking 关于 here in parallel to the main conversation is how to do 确实 great science, 尤其是 in human populations 那 are out there living. Some of 这些 men probably smoke some cannabis. I'm not saying 那 减少 sperm count. It 可能 减少 sperm motility, 然而. 我们 covered 那 in the podcast. Now all the cannabis folks go, "Well, so 和 so got so 和 so pregnant when they were doing a lot of weed." 和 I 总是 say, "Okay, well, there are a number of other factors," right? 但 alcohol, there's frequency of ejaculation, right? The requirement to abstain 对于 48 to 72 小时 to up to five 天 prior, et cetera. All 这些 factors 那 men may 或 may not faithfully report, 但 你 assume 那 if some are telling the truth 和 some aren't, 那 there's an equal distribution of 那. So all the 不同的 things.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Right? 这 is so 非常 不同的 than looking at, 对于 instance, ovarian reserve, like the number of eggs, where 你 use ultrasound 和 你 use AMH 水平 和 sure, things 可以 impact 那, 但 it's a little 不同的 than when taking-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... sperm counts.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： So thank 你 对于 doing the 研究 so carefully 和 对于 repeating them so many times. Many of the 研究 那 你've done, 你've done follow-up on 这些 sperm count 研究 across multiple years. As 你 said, the 首先 研究 was in 1992, then 你 did 一 in 2017, then there was 一 again, 和 there was an update I noticed online. So 你 are extremely thorough, 和 it probably reflects 你的 early 训练 in math 和 statistics 和 probability theory.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 你're not somebody to just go in 和 go, "Oh, yeah, in 这些 人们 那 eat a few too much of 这, then there's a little bit 更少 of 那." So if today's discussion feels like 我们're 确实 lathing 通过 这, 那's intentional.

Dr. Shanna Swan: Mm. Mm-hmm.

安德鲁·休伯曼： 和 it's 重要 对于 人们 to hear 这些 kinds of claims are not the sort of thing 那 人们 make them all over the board, 但 work like 这 needs to be done 与 an extremely meticulous eye 和 consideration of all the variables.

Dr. Shanna Swan: Well, good scientific method. Yeah.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yeah. 和 I 会 say 尤其是 与 human epidemiological work-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... 因为 of the number of potential confounding variables.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: So when I saw 那 和 actually did another 研究 to select my own 研究 和 not accept her 61 研究 那 had been published, 那 Elizabeth Carlson had published. So new 研究, came up to 更多 recent times, went back further, did it again, found exactly the same thing. Okay, so there were 三 looks at 那, 和 I thought, "Okay. I'm going to accept 这 now." Sperm count is declining.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 why? I turn to the why, okay? 因为 up until now, 我们 hadn't said anything 关于 why. 我们 just said: "Is it doing 那?" Yes. Okay. Now 我们 believe it is declining, why? 和 so then I thought quite a lot 和 talked to 人们 和 ruled out genetics 因为 it was too fast. It's 二 generations, it's too fast. Fifty years, 二 generations. So if it's not genetics, then it's environment. 和 so what is it 关于 the environment 那 could do 这? So I asked, okay, in the environment, there could be things 那 are making sperm decline. So if 你 think 关于 how 你 可能 look at 那, 你 可能 design the 研究 那 I designed next, which was another 研究. 和 by the way, 这 preceded the AGD. So 我们 had four cities in the United States 那 我们 picked 与 不同的 environments, 和 then 我们 got men to come in, 和 我们 used the same equipment at each place. 我们 used the same method of selecting the men. The technicians were trained centrally at UC Davis. 我们 had 非常 good quality control, so samples were sent 大约 every quarter to make sure 那 everybody was measuring things the same way. 我们 didn't want drift, right?

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 then 我们 got their urine, 和 那's how I had 那些 urine samples. So if 你 wanted to do 这 研究 和 你 wanted to get a representative sample of men, where 会 你 go? 因为 I 可以't ask a guy in the street to give me a semen sample, right? It's not something 你 get 非常-- So I thought, "How 可以 I get a representative sample, which 会 teach me something 关于 a larger population called the parent population?" So here's a sample, it 应该 represent the parent. So how do I ensure 那? 和 what I decided was to sample partners of pregnant women.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 因为 pregnant women all come to medical care, almost all. 和 if their partners 会 give a semen sample, then 我们 have a representative sample-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... 和 我们 know what 我们're looking at. So 那's what 我们 did. So the semen 研究 is the 研究 of partners of pregnant women. 和 of course, they'll have slightly higher semen quality 因为 they got their partner pregnant. 和 so 我们 had their urine, 我们 had their 血液, 和 我们 looked at their semen quality, 和 then 我们 decided to look at pesticides. 和 the reason 我们 look at pesticides was 因为 there was a lot of gradation across 我们的 four centers in pesticide use. 和 what 我们 found was 确实 extraordinary, 那 men who were living in central Missouri, where I was living at the time who were in the middle of an agricultural belt where there was spraying all the time 对于 soybeans 和 so on. 那些 men had half as many moving sperm as men in Minneapolis.

安德鲁·休伯曼： Whoa.

Dr. Shanna Swan: Whoa. Huge, right? 和 then 我们 went 一 step further, 和 within Missouri, 我们 looked at a sample of men who had 非常 high sperm parameters 和 非常 low sperm parameters, 和 showed 那 five pesticides were significantly higher in the men 与 the low sperm parameters. 那 include motility 和 morphology, all the parameters.

安德鲁·休伯曼： So 这些 are pesticides 那 are being sprayed in the 空气 on crops. 你 mentioned soybeans. What other types of crops?

Dr. Shanna Swan: I don't know.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: I don't remember. 那 was a while ago.

安德鲁·休伯曼： So plant 和 fruit crops, presumably.

Dr. Shanna Swan: Yeah, whatever they were growing in Columbia, Missouri at 那 time.

安德鲁·休伯曼： Mm-hmm. 和 just to make sure I understand, it's not 那 the men need-

Dr. Shanna Swan: Soybeans. Corn 和 soybeans.

安德鲁·休伯曼： Corn 和 soybeans.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 但 我们're not talking 关于 eating corn 和 soybeans.

Dr. Shanna Swan: No.

安德鲁·休伯曼： 我们're talking 关于 living in an area where pesticides are being used by, I guess it-

Dr. Shanna Swan: 但 actually-

安德鲁·休伯曼： Is it still called dust crop?

Dr. Shanna Swan: Yeah, 我们 didn't go 进入 how they got 这些. 我们 just looked in their urine, 和 there were the metabolites. The metabolites don't get in their urine unless they were exposed.

安德鲁·休伯曼： Exposed 通过 the 空气 或 exposed by eating corn-

Dr. Shanna Swan: 我们 don't know

安德鲁·休伯曼： ... 和 soybeans. 我们 don't know.

Dr. Shanna Swan: 我们 don't know.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: 我们 don't know. 但 这 was not a particularly-- 我们 didn't sample farmers only 或 anything like 那. So it was whoever came 进入 the-- Remember how 我们 got 这些 men. Their wives were pregnant. They were having prenatal care at the University of Missouri. So 那's where 我们 got them. Whoever happened to come in to the prenatal clinic 和 agree to be in 我们的 研究, the male's urine was measured 对于 这些 pesticides.

安德鲁·休伯曼： I'm sure a number of 人们, including myself, are wondering in what other products are 这些 five pesticides present. Are 这些 commonly used pesticides, 或 is it something 关于-

Dr. Shanna Swan: They're called the triazine pesticides. Atrazine was the most widely used, 和 it's in huge use 大约 the world. It's 一 of the largest commercial pesticides. So 这些 were 非常 big players in the pesticide field.

安德鲁·休伯曼： A relevant theme there 会 be, maybe 我们 could take a moment 和 talk 关于 Atrazine 和 its effect on male sexual behavior in amphibia. 和 我们'll come back to- ... the sperm 研究 因为-

Dr. Shanna Swan: Sure

安德鲁·休伯曼： ... when I was a graduate student at UC Berkeley, I had the wonderful experience of taking a course 从 the now, I think 你 mentioned he's a dean. There are multiple deans on campuses. Tyrone Hayes is a wonderful researcher who established a link 通过 his 研究 between Atrazine exposure 和 male sexual behavior of amphibia.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Could 你 elaborate on 那 result?

Dr. Shanna Swan: Yeah. So Tyrone 首先 caught frogs in the wild, in environments 那 were 更多 或 更少 exposed to Atrazine 和 showed effects on development 和 sexual behavior. Then in his lab, he actually exposed them, so he knew exactly who was exposed 和 to how much. 和 he showed 那 the-- I 可以't tell 你 what percent, 但 a significant number of frogs exposed to 这 pesticide, Atrazine, chose to mate 与 other male frogs.

安德鲁·休伯曼： Tried to mate 与 other male frogs, presumably unsuccessfully.

Dr. Shanna Swan: Well, they mounted them.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: He has photos of the males mounting males.

安德鲁·休伯曼： 和 so presumably 这 is a neural change 那 occurred.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Neuroendocrine change.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 但 ultimately neural, since mounting behavior is controlled by-- Actually 我们 now know the hypothalamic nuclei 那 control 这. David Anderson, who's been on 这 podcast, has 人们 in his laboratory, including a former graduate student of mine working on 这 具体的 issue of what the circuitry is. 那's a remarkable result. It's been used 和 misused out there in the media 和 in popular culture. 但 if nothing else, it suggests 那 the organization of the neural 回路 和 neuroendocrine 通路 那 control sexual, I don't want to say partner, 因为 it is a mating thing, frogs aren't monogamous, 但 sexual preference are significantly impacted by 这 Atrazine.

Dr. Shanna Swan: Yes. 和 it suggests 那 there are other environmental chemicals 可以 as well. 和 I don't know if I'll have time to go there, 但 I did work on neurodevelopmental outcomes in relation to prenatal phthalate exposure. 和 so I think the overarching idea here is 那 the 大脑, like the genitals, is sexually dimorphic. 和 there's many 人们, by the way, who 会 take offense at 那.

安德鲁·休伯曼： 确实?

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： I think there's-- Going back to the-

Dr. Shanna Swan: I know

安德鲁·休伯曼： ... work of Frank Beach in the-

Dr. Shanna Swan: I know

安德鲁·休伯曼： ... Psychology Department at UC Berkeley-

Dr. Shanna Swan: I know

安德鲁·休伯曼： ... showed 这 in beagles. It's been shown in pretty much-

Dr. Shanna Swan: I know

安德鲁·休伯曼： ... every species.

Dr. Shanna Swan: 但 I'll just tell 你 那-

安德鲁·休伯曼： 但 it's not a better, worse. I think 这 is what-

Dr. Shanna Swan: No

安德鲁·休伯曼： ... 人们 need to hear. Like dimorphic does not mean better, worse.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： It means 不同的.

Dr. Shanna Swan: 不同的. Right.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: 和 there are, 对于 example, advantages to spatial reasoning in a male, which are related to testosterone. Right? 你 know 那. So spatially-

安德鲁·休伯曼： I think they're-- Yeah. My understanding of 这 literature, 和 I'm not an expert in 这 particular aspect, which is the behavioral phenotypes.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Like the medial preoptic area of the hypothalamus is known to be sexually dimorphic-

Dr. Shanna Swan: Mm-hmm

安德鲁·休伯曼： ... dependent on testosterone-

Dr. Shanna Swan: Mm-hmm

安德鲁·休伯曼： ... converted 进入 estrogen-

Dr. Shanna Swan: Mm-hmm

安德鲁·休伯曼： ... 期间 development, et cetera. 和 there's just so much 证据 of 这.

Dr. Shanna Swan: Mm-hmm.

安德鲁·休伯曼： How it links to behaviors, I think 可以 be reasonably placed 进入 ethologically relevant, evolutionarily logical-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... arguments when talking 关于 rodents 或 beagles 或 even rhesus macaque monkeys. I think where 人们 get a bit inflamed is when 人们 try 和 take the sexual dimorphisms 那 have been observed in animal brains 或 even in human brains 和 tack 那些 to 具体的 abilities 或 lesser abilities. I think 那's when 人们 sort of go, "Wait a 秒, I have much better sense of direction than my husband." 和 你 go, "Well, yeah." 和 then 你 go, well, does 那 mean 那 she has higher testosterone than him? 和 then maybe, 和 pretty soon 你're-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... in almost a no man's land, a no person's land of- ... confounding variables.

Dr. Shanna Swan: 你're right.

安德鲁·休伯曼： Right? 但 I 确实 appreciate 那 你 raised 这.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 和 also 那 你 said it 和 I didn't, 因为 I feel safer 那 way.

Dr. Shanna Swan: 但 look, there is a 非常 simple, outdated questionnaire, 和 it's play behavior. It's called the PSAI.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: It's been used 对于 years. I don't know if 你've heard.

安德鲁·休伯曼： It's a rough 和 tumble play.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: Yes. 和 there are 24 questions on there, 和 they are sexually dimorphic, I guess 你 could say. My child likes to play 与 dolls. My child likes to play dress-up. My child likes to play rough 和 tumble, et cetera. 和 我们 gave 那 questionnaire to 我们的 population 和 looked at the answers 那 the mothers gave. Both in 我们的 population, by the way, 和 a Swedish population of a colleague there, Gustaf Bornhagh. 和 what 我们 found, higher phthalate 水平, 这些 anti-androgenic phthalates were associated 与 更少 masculine, male typical play in 我们的 male boys. So-

安德鲁·休伯曼： 这 is phthalate exposure to the-

Dr. Shanna Swan: In utero

安德鲁·休伯曼： ... to the mom, baby is born in the young human child.

Dr. Shanna Swan: Yeah, I think it was four years of age.

安德鲁·休伯曼： Four years of age, 更少 rough 和 tumble type play-

Dr. Shanna Swan: 那's right

安德鲁·休伯曼： ... among the boys whose mothers were exposed to 更多 phthalates 期间 a critical period of development.

Dr. Shanna Swan: Now 你 可以 see 那's a politically loaded issue now.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: There's a-

安德鲁·休伯曼： Well, I think 我们're-- Let's have some fun 与 这 in the scientific sense. The notion of dimorphism is, okay, male 和 female brains are 不同的, right? 和 male, female defined in almost all 那些 研究 as presence of a Y chromosome. 和 then 人们 say, well, there's XYY, 和 then there's XXY. Okay. 但 most of the time 你're talking 关于 XX chromosome 或 XY chromosomes at birth. Forget everything else 对于 the moment. 这些 are 总是 distributions. 这 is what I think 人们 need to know. 这 is not 二 hills of 数据 separated by a valley. 这些 are overlapping distributions.

Dr. Shanna Swan: Correct.

安德鲁·休伯曼： Right? So 你 get males 与 a, quote-unquote, female-like distribution. 你 get females 与 a, quote-unquote, male-like distribution. 和 I think as long as 我们 acknowledge 那, then 我们're just talking statistics.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 我们're not placing any cultural 或 any value on it 确实 whatsoever.

Dr. Shanna Swan: Right. 但 if 你 could make the analog to the anogenital distance, it's kind of 相似的.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 你 have the same exposure, phthalate exposure. 你 have something change statistically. 我们 don't see huge differences in the boys' genitals.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 我们 don't see huge-- 这些 kids have not been scanned, so 我们 don't know how their brains look. 但 based on their answers, 我们 don't see huge differences. 我们 see tendencies. 我们 see they are 更多 可能, if they had been exposed to 这些 phthalates, to want to play dress-up 和 have tea parties. 更多 可能. Doesn't mean 那 they're all going to, 但 那's the direction, 和 so on. So I think 我们 have to just think 关于 更多 可能, not absolute. Yeah.

安德鲁·休伯曼： 和 of course, there are also the socio-biological variables, such as if a young boy has a sibling 那's a sister, there's 更多 可能 to be dresses 大约, right?

Dr. Shanna Swan: 我们 controlled 对于 那.

安德鲁·休伯曼： If he has 二 older brothers, there 可能 be 更多 rough 和 tumble play happening in the house. 和 I have some friends 那 are women who have older brothers, 和 那些 women are, some of them roll jujitsu 或 do-

Dr. Shanna Swan: Sure.

安德鲁·休伯曼： 和 I know some women who are only children who do martial arts 和-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... fight.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： So, I think 那 none of 这 is deterministic-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... as 我们 know. I-

Dr. Shanna Swan: 但 let me just add, 我们 did control 对于 the sex of the older sibling, 和 我们 also asked 关于 the parents' attitude towards same-sex play.

安德鲁·休伯曼： Mm.

Dr. Shanna Swan: So how 会 你 feel if 你的 male child played 与 dolls? 会 你 be discouraging? 会 你 encourage-- 因为 it has a lot to do 与 what's in the house. If 你 say, "Does 你的 child play 与 dolls?" Well, what if there were no dolls, right?

安德鲁·休伯曼： 这 is super interesting to me.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： I don't want to reveal too much, just 因为 it's just an N of 一. 但 I grew up in a household where I have a sister, 但 then 之后 a certain age, I received 非常 strong messages 关于 what sorts of play were gender appropriate. 和 I think I also just naturally defaulted to-- There were a bunch of boys 那 lived in my neighborhood. They had older sisters, so all the sisters hung out together. It's kind of interesting. 和 all the younger brothers pretty much hung out together. 和 the guys 那 didn't have siblings 或 had brothers 对于 siblings. So there was a 确实 strong divergence. 但 那 was in the '70s 和 early '80s when things were, let's just say culture was 更多 dimorphic then. Clearly.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： There were television shows like "All in the Family," which the entire basis of the show was the wife going back to work 和 the husband being confused 关于 it. Nowadays, 人们 会 go like, "What? 那's wild." I have to ask, 因为 I know 人们 are wondering, 和 I'm wondering, what are some non-pesticide sources-

Dr. Shanna Swan: Oh

安德鲁·休伯曼： ... of phthalates 那 我们 have agency over, 那 我们 可以 take control over?

Dr. Shanna Swan: Right. So let me correct 你. It's not the sources of phthalates necessarily. Pesticides, there are phthalates in pesticides.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 但 那's not the worst player in the story. If 你 look at the 不同的 classes of exposures 那 are hormonally active, right, pesticides are, phthalates are, bisphenols-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... like bisphenol A.

安德鲁·休伯曼： BPA.

Dr. Shanna Swan: BPA.

安德鲁·休伯曼： Yep.

Dr. Shanna Swan: Certain metals are. There's the PFAS chemicals. There's all 这些 不同的 classes, right?

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 if 我们 want to go in, excuse me, 进入 what in 我们的 daily life exposes us to 这些 things-

安德鲁·休伯曼： Okay

Dr. Shanna Swan: ... 那's another story-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... 那 我们 可以 talk 关于, 但 they're going to be 不同的 depending on the class, right?

安德鲁·休伯曼： So let's throw 我们的 arms 大约 all of 那些 对于 the moment, 和 I'll just ask 你, given 那 你're an expert in 这 area, what are the top 三 to five sources of endocrine disruptors 那 我们 have agency over? 和 let's forget 关于 pregnancy 对于 the moment, since 我们're all out of the womb, if 我们're listening to 这. Some 人们 会 be pregnant as they listen to it, 但 会 你 say it's drinking out of plastic bottles? Is it laundry detergent? Is it rubber tires 那 are cascading down on us 通过 the 空气, 和 我们're inhaling them? Presumably all of the above, 但 which ones 那 我们 have agency over do 你 think are the most, let's just say, concerning where 人们 could make better choices?

Dr. Shanna Swan: I 会 say foodborne exposures. Exposures in the food, in the food packaging, in the food storage, in the cooking utensils. 我们 可以 go 通过 the various things, 但 我们're doing 那 all the time. 我们're eating all the time. 我们're getting food 进入 us, 和 这些 are bringing in, in a way 那 我们 have some control over, some agency over.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 我们 可以 make changes in 我们的 foods. 非常 close to 那 is drink. Food 和 beverage. So 首先 of all, I've talked 关于 这 a lot. I've written 关于 it in my book. I'm also, as 你 know, involved in a movie where in the movie, 那 可能 be good time to talk 关于 那.

安德鲁·休伯曼： Sure.

Dr. Shanna Swan: What 我们 do in the movie, the movie is 关于 six couples 那 are infertile. Okay? They haven't been able to conceive in 12 months. 那's the definition. 和 then a company 那 I work 与, Million Marker out of Berkeley, has a trained staff 那 interviews them. Not only them, 但 anyone who signs in to 这 company. Interviews them 和 asks them what they use. What do they use 对于 their facial care? What do they use 对于 their shampoo? What do they use 对于 their cleaning products 和 their laundry detergent? 和 what do they store their food in? 和 on. So 这 is long inventory 那 they take of all products 那 人们 are aware of using, okay? 和 based on 那, 我们 identify 可能 bad players in the list. So how 我们 do 那 is another, 我们 可以 talk 关于 那 later. 但 then in the film, 和 in 这 little-- It's actually an experiment 那 I designed, 和 called an intervention, 和 我们 are then intervening in their exposures by changing out 这些 things 那 they told us. So 我们 会 tell them, "Don't use any product 与 fragrance," 对于 example. 那's a major source of exposure to phthalates.

安德鲁·休伯曼： Any product?

Dr. Shanna Swan: Any fragrance product. If fragrance is added-

安德鲁·休伯曼： So no perfume, no lotions.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Soap 与 fragrance.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Even essential oil fragrances like lavender.

Dr. Shanna Swan: Essential oil is a tricky-

安德鲁·休伯曼： Right. It's a mix.

Dr. Shanna Swan: It's a mix.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: Yeah. So 那's guarded. 但 anything, 你 know-

安德鲁·休伯曼： Spray deodorants-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... roll-on deodorants.

Dr. Shanna Swan: Yeah. Laundry detergent 与-

安德鲁·休伯曼： Shampoo.

Dr. Shanna Swan: Yep, in shampoo. If 你 可以 smell it, it's probably affecting 你的 激素.

安德鲁·休伯曼： I'm so happy 关于 这 answer, not 因为 I have any stake in any company related to fragrance-free stuff, 但 I have a 非常 strong sense of smell, 和 I either love 或 hate smells, 和 I hate synthetic smells. Like going 通过 the duty free, 尤其是 in a European airport-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 与 all the perfumes.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 和 I'm just I'm trying to hold my breath.

Dr. Shanna Swan: I know.

安德鲁·休伯曼： It feels like I'm breathing poison.

Dr. Shanna Swan: I know.

安德鲁·休伯曼： Well-

Dr. Shanna Swan: Well, 你 are, actually.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: Yeah. In some sense.

安德鲁·休伯曼： 和 most soaps, right.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Super interesting. So 那's 你的 primary intervention, is to tell them-

Dr. Shanna Swan: Exactly

安德鲁·休伯曼： ... get rid of anything 与 fragrances.

Dr. Shanna Swan: No.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: 那's only 一 thing 我们 get rid of. So then 我们 talk 关于 how the plastics 那 they use to store their food. Food storage containers, try to get them to get rid of 那些 if they're made of plastic. 我们 try to get them to get rid of their non-stick pans 因为 of the PFAS chemicals 那 are in 那些, 和 so on 和 so forth. So 我们 go 通过 all steps of their life 和 try to tell them how to make changes 那 会 减少 their exposure.

安德鲁·休伯曼： 但 presumably also changes like if the man is obese, 对于 instance, 你 可能 Have him walking a bit 更多.

Dr. Shanna Swan: No.

安德鲁·休伯曼： No? 你 don't touch any of 那?

Dr. Shanna Swan: Well, 你 see, Andrew, if 我们 did 那, 我们 会 be mixing up 二 interventions. 我们 会 be mixing up an obesity intervention-

安德鲁·休伯曼： I see. 这 is a 研究.

Dr. Shanna Swan: 这 is a 研究, right.

安德鲁·休伯曼： I'm sorry. I thought 那 这 group is missioned 与 helping couples get pregnant.

Dr. Shanna Swan: No, no.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: 这 is a 研究 to look at what happens if 你 make 这些 product-related changes.

安德鲁·休伯曼： Great. Just product-related changes.

Dr. Shanna Swan: Right. Exactly.

安德鲁·休伯曼： Love it. Okay.

Dr. Shanna Swan: Exactly.

安德鲁·休伯曼： Thank 你 对于 那 clarification.

Dr. Shanna Swan: 我们 会 love to do, 和 probably 会 do, another 研究, separate 一, on obesity.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 a lot of 这些 chemicals, just to let 你 know, are obesogens. They 增加 obesity.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: There's a book out called "Obesogens." 你 可以 read 关于 them. 和 so, there is some overlap, so by 减少 some of 这些 chemicals 那 are in 你的 food storage containers, 你're also 减少 obesogens. So it's not a clear yes/no. 我们 gave them a box, each couple. I went to their house, six couples 大约 the United States, 与 a big box, 和 in 这 box are 这些 alternative products. 和 so, straws 和 bamboo spoons 和 $500 per box, I think it was, approximately. It had to do 与 their personal exposure. 和 then they made 这些 changes. Now, unlike another 研究 那 你 reported, they are, at the end, quite happy to keep doing 这, by the way. They love 这. They love doing 这. It was so gratifying-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... to see 那 they felt, in many, many ways, their life got better. I'm pretty careful in what I-- So I hesitate to say 这 因为 the 数据 is not hard, 但 the impression is 那 they are happier. They're sleeping better. They report 更多 能量 和 so on 和 so forth, having made 这些 changes. 我们 need to follow 那 up 与 hard 数据.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: I'm not writing 那.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: 但 I 可以 say, 和 I 可以 write, 那 they felt 非常 positive 和 我们're going to go back 和 see if they did continue.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 我们 need to do 那. 但 at the end of the 三 months, 和 hopefully in six months, they are still making 这些 changes in their lives.

安德鲁·休伯曼： Did 你 collect 数据 on whether 或 not they were able to conceive 之后 having made 这些 changes?

Dr. Shanna Swan: Yes, 我们 did, 但 I actually 可以't talk 关于 那.

安德鲁·休伯曼： 可以't talk 关于 it until the babies are born. Just kidding.

Dr. Shanna Swan: 和 我们 did get their sperm count at the beginning 和 the end 和 had some 非常 interesting 数据 on 那, which-

安德鲁·休伯曼： Too early to report.

Dr. Shanna Swan: Yeah. Too early to report.

安德鲁·休伯曼： Let me ask 你 这 then, 和 I appreciate not wanting to share 具体的 结果 until-

Dr. Shanna Swan: Yes

安德鲁·休伯曼： ... all the 数据 are in 和 it's published. If somebody listening were having trouble conceiving-

Dr. Shanna Swan: Mm

安德鲁·休伯曼： ... 对于 12 months 或 更多, are the sorts of replacement product interventions 那 你're talking 关于 here things 那 你 会 at least feel comfortable saying 可能 be a good place to start 或 to explore?

Dr. Shanna Swan: Absolutely.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Absolutely. There's no harm. None of the changes are putting 人们 at risk 或 doing anything 那 could be harmful to them.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: I'm sure of 那.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 我们're 非常 careful.

安德鲁·休伯曼： 和 some are going to be cost-saving.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： 和 I think 那's worth-- Like drinking out of plastic bottles far 更少, if at all. Just 对于 reasons related to wanting to 减少 waste, I use a mason jar 或 I use 这些 或 ceramic. 尽管 你'll probably tell me 那 the lining on the ceramic mug 可能 have endocrine disruptors. No, I don't-

Dr. Shanna Swan: I don't think so.

安德鲁·休伯曼： Okay, great. Okay. Well, then I'll keep drinking.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 但 it's 非常 reassuring to me 那 there are things 那 我们 可以 do in terms of cost-saving elimination 或 replacement of consumables-

Dr. Shanna Swan: Buying in bulk

安德鲁·休伯曼： ... 那 可以 改善 endocrine status, maybe fertility also.

Dr. Shanna Swan: If 你 可以 buy in bulk-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... bring a container to the store 和 fill it up, a glass jar, instead of buying something in plastic-

安德鲁·休伯曼： Mm

Dr. Shanna Swan: ... 你're winning on both ends 因为 那些 bulk products are cheaper.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 一 of the things I did 与 the couples was go shop 与 them, 和 我们 went 大约 和 我们 looked at various products. 和, 对于 example, 我们 looked at the produce 和 there was the option to buy freestanding bunches of lettuce, heads of lettuce, 或 wrapped up in plastic bunches of lettuce. 和 I said, "Let's compare the price." I actually didn't know until 我们 did it, 但 the freestanding unwrapped lettuce was cheaper. 和 I think 那 makes sense, 因为 there's work involved in wrapping it up in the container 和 so on. 和 so not only are 你 getting something 那's 更多 toxic, 但 it's 更多 expensive.

安德鲁·休伯曼： Mm-hmm. When it comes to 减少 BPA exposure-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 和 some of 这些 forever chemicals-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 那 你 mentioned, seems like 减少 fluid intake 从 plastic vessels is going to be number 一.

Dr. Shanna Swan: The primary source of BPA is in the lining of cans. So any drink 或 soup 或 anything 那 comes in a 可以 is going to be-

安德鲁·休伯曼： Any 可以. All cans

Dr. Shanna Swan: ... any 可以, unless it's a high-end elite company 那's made the change 从 BPA to an alternative lining, 和 they'll say 那.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 by the way, BPA has some bad relatives, such as BPS 和 BPF, 和 maybe 你'd be interested in 这 story. So when it came out 那 BPA was estrogenic, which is what it is, 和 by the way, it's kind of the evil twin of phthalates 因为 phthalates are anti-androgenic 和 BPA is estrogenic, 和 phthalates make plastic soft 和 BPA makes plastic hard. 你 don't want either. Okay. So when 这 came out 那 这 was a bad thing, the manufacturers started selling things 那 say BPA-free. I'm sure 你've seen 那. The trick is 那 instead of BPA, they use BPS-

安德鲁·休伯曼： Sneaky rats

Dr. Shanna Swan: ... 和 BPF.

安德鲁·休伯曼： So sneaky.

Dr. Shanna Swan: 和 这些 are chemicals, 这些 are lookalikes, they're analogs, 和 they're just as harmful.

安德鲁·休伯曼： Sneaky.

Dr. Shanna Swan: So-

安德鲁·休伯曼： I'm not a conspiracy theorist, 但 it's just so dirty. It's so dirty. Right now is a 确实 重要 time to be having 这 discussion 因为 there's been a lot of movement on Capitol Hill, 和 there's been a lot of movement on social media 关于 trying to call 注意力 to metabolic syndromes 和 highly processed foods 和 issues like 这, 和 it's become, unfortunately, politicized. I hear 这 stuff, 和 I just think to myself, the only good faith 那 我们 可以 确实 trust is 我们的 own desire to be healthier 和 to have 我们的 families 和 friends be healthier, 和 to try 和 consume 和 not consume things on the basis of 那. My belief is 那 我们 可以't trust any larger agency to either protect 或 harm us. They're going to do what they're going to do.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 我们 just have to be informed.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： As opposed to trying to dismantle the 系统 那 led to 这, which just seems infinitely complicated. Maybe 你 可以 do 那, 但 I'm far 更少 optimistic. 和 now 那 I'm 49 years old, I 可以 say things like, "Now 那 I'm 49, I feel like..." 但 what 你're saying is 确实 重要. If I look at a 可以, it says BPA free, doesn't mean anything. It could have BPSs 或 other endocrine disruptors.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： So drinking out of glass vessels-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... drinking out of ceramic vessels-

Dr. Shanna Swan: Metal

安德鲁·休伯曼： ... metal, 但 not cans, not metal cans, not aluminum cans.

Dr. Shanna Swan: Right. Not cans, no.

安德鲁·休伯曼： Goodness.

Dr. Shanna Swan: 但-

安德鲁·休伯曼： Okay

Dr. Shanna Swan: ... 你 可以 get a metal 水 bottle 那's not lined 与 BPA.

安德鲁·休伯曼： Steel.

Dr. Shanna Swan: Steel. Yeah.

安德鲁·休伯曼： Steel.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 和 is it true 那 microwave safe just means 那 the plastic won't melt in the microwave, 但 it's-

Dr. Shanna Swan: Do, 从不 put plastic in a microwave. So here's the story. The BPA, phthalates, plasticizers are added to the plastic, 但 they're not chemically bound to it. Okay? So if 你 put anything in a container 那 has 这些 chemicals in it, 和 then put it in a hot environment, they 会 come out of the plastic 和 go 进入 the food. So if 你, in a microwave 或 你 put 你的 bottle in the car 和 the sun comes in 和 it warms up the bottle, 和 then the stuff goes 进入 你的 水. 你 don't want to mix 这些 chemicals 和 你的 food, 但 if 你 do, the worst thing is to do it in a heated environment.

安德鲁·休伯曼： I think 关于 all the food 那 was consumed in college in the '90s 和 2000s, like the Cup of Noodles 与 the styrofoam, the-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... things in packaging.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Stuff like 那 is pretty straightforward to eliminate once 一 understands 和 decides.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Then 我们 start getting 进入 the 更多 nuanced thing of like, okay, 你 可以 buy a 确实 nice tasting, anyway, grass-fed, grass-finished steak, 但 it's wrapped in plastic. Well, 或 你 可以 go to the butcher, 但 most 人们 don't have time to go to the butcher. 或 你 可以 get strawberries at the farmers market, blueberries at the farmers market, which is what I try to do, 但 sometimes I buy strawberries at the market, 和 they have 那些 plastic flip-top things.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 和 of course, I recycle the plastic. How bad is it if 你 rinse the strawberries off 与 good clean 水 那 were in the plastic container? Are 你 s-

Dr. Shanna Swan: 我们 have to do 那 experiment. I don't know.

安德鲁·休伯曼： Yeah. So it sounds to me like not drinking out of cans, not drinking out of plastic bottles. It's going to be not microwaving plastic ever. 和 in general, just avoiding plastic intake.

Dr. Shanna Swan: If 你 可以 afford it, buy organic. So 你're going to avoid the pesticides, 和 then phthalates are actually added to pesticides. 和 they're added 因为 they 增加 absorption. So 你 want 你的 pesticides to get 进入 the plant, right? 和 to kill the bad stuff 和 insects. 和 so the same property of phthalates 那 makes them good 对于 pesticides also makes them good 对于 我们的 hand cream. Just mentioning. Absorption. Anything 那's absorbed in the 身体 is going to have phthalates in it. 和 it also holds scent 和 color, so it's added to 那些 scents, 和 it's also added to 你的 lipstick 和 to 你的 color, whatever 你 put on 你的 face, 和 so on. Anything 那 holds scent 和 color, 那's going to be phthalates. Sorry.

安德鲁·休伯曼： I've been accused online of being a sunscreen truther. I'm not a sunscreen truther. I'm going to keep repeating 这 as many times as I 可以. I understand 那 UV damage to the 皮肤 可以 cause certain cancers. I get 那. I agree 与 那. The 数据 are pretty clear to me based on having researched 这 pretty extensively 和 talked to many, many 人们, including dermatologists, 那 mineral-based sunscreens like zinc oxide 和 titanium dioxide, 但 certainly zinc oxide, are safer than the chemical sunscreens. A lot of 人们 get upset when I say 那, 和 they say, "Well, in Europe, there's tons of 证据 那 the chemicals-based sunscreens are 从不 safe." Okay, fine. 你 use them. I'm not going to. The point being 那 UV damage is bad. There are ways to protect ourselves 从 the sun, including physical barriers like clothing, hats, et cetera. 但 pretty much all sunscreen 那 I'm aware of is designed to be absorbed. So what do 我们 do if 我们 want to get some UV protection 从 whatever kind of sunscreen 我们 deem safe 对于 ourselves, 但 我们 want to avoid 这些 exposures to 这些 other things? What do 我们 do?

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Do 我们 have to hunt 确实 carefully 对于 the right sunscreen?

Dr. Shanna Swan: Yeah. I think 那's a good idea. Are 你 familiar 与 Environmental Working Group?

安德鲁·休伯曼： Is it another 一 out of the Bay Area?

Dr. Shanna Swan: No.

安德鲁·休伯曼： Oh, okay. All right.

Dr. Shanna Swan: I don't know actually where they are. They're pretty big.

安德鲁·休伯曼： Sounds familiar, 但-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... no, I 可以't say I'm familiar 与 them.

Dr. Shanna Swan: So they have consumer guides. So Environmental Working Group, I'm not part of them, 但 I like their work. 和 in 这些 consumer guides, 你 可以 put in the product, 和 they have categories. 你 可以 put in sunscreen. If 我们 had time, 我们 could do it right now. 和 then 你 可以 put the name in 对于 你的 sunscreen, 和 it'll give 你 a number. 和 then if the number is 更少 than 10, it'll tell 你 why.

安德鲁·休伯曼： Mm-hmm. Are they independent of any-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... fund-

Dr. Shanna Swan: They're totally independent

安德鲁·休伯曼： ... funding. Yeah. 那 question 会 probably come up 对于 你, too. 人们 会 say, "Where does she get her funding?" 人们 get 非常 suspicious 关于 这.

Dr. Shanna Swan: I 可以 tell 你.

安德鲁·休伯曼： Yeah, 那'd be great. Yeah.

Dr. Shanna Swan: Yeah. So I am a tenured professor at Mount Sinai, get some salary there 因为 I'm only part-time. 和 I have a funder, 一 funder, who funded my sperm decline, 秒 sperm decline analysis, 和 the publicity of my book. So it's a foundation. I won't-

安德鲁·休伯曼： So it's philanthropy.

Dr. Shanna Swan: Yeah, it's philanthropy.

安德鲁·休伯曼： Yeah. Okay.

Dr. Shanna Swan: Yeah. 和 it's actually not a lot of money.

安德鲁·休伯曼： 和 so there's no reason to think 那 anything 那 你're telling us is linked to the food industry 或 an alternative-

Dr. Shanna Swan: I-

安德鲁·休伯曼： ... product 或 anything. Yeah

Dr. Shanna Swan: ... I'm 非常, 非常 careful not to endorse any product-

安德鲁·休伯曼： Great

Dr. Shanna Swan: ... 因为 I don't want 那 complication.

安德鲁·休伯曼： Yeah. Thanks 对于 clarifying 那.

Dr. Shanna Swan: Sure.

安德鲁·休伯曼： I wasn't suspicious, 但-

Dr. Shanna Swan: Right. Yeah

安德鲁·休伯曼： ... 但 I think nowadays 人们 have just been taught to, appropriately so-

Dr. Shanna Swan: Mm-hmm

安德鲁·休伯曼： ... they've been taught to say, "Well, wait, where does 这 funding come 从?" 因为 a lot of the 研究 那 led to the food pyramid, 对于 instance, 人们 were under the impression 那 somehow 那 was biased by companies 那 were funding the work. 和 I don't know, I haven't done the forensics on 那. I don't have the time 或 the 能量.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： All I know is 那 when it comes to what 人们 eat, when it comes to what 人们 put on their 身体, it becomes a 非常 personal thing, 和 it's woven in 与 a lot of psychological 和 emotional issues.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yeah. Okay. What are a few things 那 你 do 和/或 avoid in light of what 你 know 关于 这些 endocrine disruptors? 和 by the way, it goes 没有 saying 那 你're in spectacular cognitive 和 physical shape 对于 any age, 但 it's 确实 remarkable. I feel comfortable sharing 这 因为 someone else published it online recently. 你 are soon to enjoy 你的 what birthday?

Dr. Shanna Swan: 89th.

安德鲁·休伯曼： 89th birthday. Amazing. 和 与 all the talk 关于 longevity, cognitive 和 physical longevity, everyone's thinking, including me, like, "What does she do?" "Well, she avoids all 这些 endocrine disruptors." 和 she has a wonderfully rich life of curiosity 和 other things. 但 yeah, what are some other things 那 你 do 和 avoid in light of what 你 know, 对于 which there may 或 may not be a controlled 研究, 但 I think 我们're all just curious. 我们'll frame 这 as what 你 do.

Dr. Shanna Swan: So, 水. 我们的 水. I worry 关于 the 水. I studied 水 对于 a long time in my past life. So 我们 actually distill 我们的 水. So 我们 have a tabletop distiller. My husband Steven cleans it out. There's a lot of gunk in it, by the way. Even though it's San Francisco 那 has clean 水, at the end of the 天, 之后 你've distilled the 水, there's a lot of gunk in it.

安德鲁·休伯曼： So 你 distill the 水, so 这 is not reverse osmosis.

Dr. Shanna Swan: No. Distilling.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Yeah. So it's steam distilled, 和 then it condenses in a glass container, 和 then 我们 put 那 in glass containers in the fridge. 和 it tastes 确实 good, by the way. 确实. Somebody was just over, 和 he said, "这 tastes like melted snow."

安德鲁·休伯曼： Mm.

Dr. Shanna Swan: I thought it was lovely.

安德鲁·休伯曼： 和 你 use 那 对于 drinking-

Dr. Shanna Swan: Everything

安德鲁·休伯曼： ... 对于 coffee, 对于 tea.

Dr. Shanna Swan: Everything.

安德鲁·休伯曼： 对于 cooking, too. If 你 make rice, 你're using distilled-

Dr. Shanna Swan: Actually, no.

安德鲁·休伯曼： No.

Dr. Shanna Swan: No. 但 对于 ice cubes 和 whenever I 可以 think 关于 it. 我们 可以't use too much 因为 你'd be too busy all 与 distilled-

安德鲁·休伯曼： Right.

Dr. Shanna Swan: 但 he does it once a 天, 和 it's just the 二 of us. So 水 is 重要. 我们 try to leave 我们的 shoes at the door.

安德鲁·休伯曼： Tell me 关于 那 一. What's 那 一?

Dr. Shanna Swan: Well, dust 那 你 bring in contains a lot of particularly the PFAS chemicals 和-

安德鲁·休伯曼： Oh

Dr. Shanna Swan: ... so 那's actually, I'm not 100% good on 那, 但 我们 try to do 那. 和 I'm careful 与 the products I put on my face. I check them out the way I suggested, Environmental Working Group. 和 I go to the farmers market. I 总是 buy organic. 但 I know 那's a cost issue 对于 some 人们, 和 an availability issue 对于 some 人们, 但 in San Francisco, 你 可以 do 那. Some areas where I don't do 更多 of what I 应该, I think, I'm starting to be aware of the chemicals in clothing. 我们 haven't talked 关于 那, 但 turns out there's a lot of, particularly in, it's a problem 对于 workout wear 因为 你're absorbing so much. 你're sweaty, 你're hot, 和 你're bringing 这些 chemicals 进入 你的 身体. 和 那 may be 一 of the interventions 那 我们 do, get a bunch of athletes to use safe clothing 和 traditional clothing 和 see what their 身体 burden is. 那's how 你 know.

安德鲁·休伯曼： So, erring toward cotton as opposed to synthetic-

Dr. Shanna Swan: Synthetics

安德鲁·休伯曼： ... materials.

Dr. Shanna Swan: Right. 和 the dyes are 重要. So 你 want maybe plant-based dyes. It's not my area of expertise. I have a colleague who I work 与 on 这, 和 I'll go 与 her advice. 但 I'm just saying 那's another area 那 I think 人们 会 soon be paying 注意力 to. There's also the area 那 is much 更多 difficult, which is what's in building materials 和 furniture. 但 a lot of 这些 PFAS 和 the flame retardants are in 我们的 furniture 和 in 我们的 building materials, 和 trying to think 关于 how to build I was asked 关于 safety in a new village 那's being built in California, by the way. 和 it's 确实 challenging to think 关于 if 你 were going to do 这 right, 和 你 were going to build a town 那 was toxic-free, how 会 你 do 那? I'm thinking 关于 那.

安德鲁·休伯曼： Mm-hmm. I'm thinking 关于 the opener of "The Simpsons" 和 doing the exact opposite, where in the opener of "The Simpsons," there's a 三-eyed fish, 和 there's the chemical plant. 和 I'm just thinking, 你 just look at the opener of "The Simpsons," 你 do the inverse of everything 那's there. The inverse of everything 那's there, including alcohol intake- ... which is robust on "The Simpsons."

Dr. Shanna Swan: Yeah. Right.

安德鲁·休伯曼： 但 interesting. So, 和 when it comes to food sourcing, 但 non-fruit, non-vegetable food sourcing, is there anything 我们 可以 do? It's so hard 对于 人们 to get eggs 从 farms. 你 可以 if 你 go to a farmers market, 但 这 stuff 可以 get pretty tricky, pretty expensive.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 和 most 人们 listening are not going to be living in Sonoma where they 可能 have a neighbor 那 has chickens 或 something.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： It's a hard problem.

Dr. Shanna Swan: It is a hard problem, 和 I think maybe 人们 asking 对于 it 更多 会 help. I don't know. In San Francisco, I'm lucky, 因为 I 可以 just get on the phone, Fresh Direct, order, 和 I know it's okay. 但 I know 那's not the case everywhere. So, I think being aware, honestly, is a 确实 big step. If 你 are aware 那 这 is something 你 want to change, 你 会 find ways to change it.

安德鲁·休伯曼： It's interesting 因为 a few years back, there was a lot of discussion 关于 dyes in children's toys, in particular, toys 从 overseas. Right? Remember, young babies are 总是 gnawing on stuff-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 和 teething. 和 there was a lot of 注意力, like, "Hey, what's in 这些 sippy cups?" 和 my understanding is toys 和 sippy cups, 和 my understanding is 那 BPAs were banned 从 sippy cups.

Dr. Shanna Swan: Phthalates.

安德鲁·休伯曼： The phthalates. Excuse me.

Dr. Shanna Swan: Based on my work.

安德鲁·休伯曼： Based on 你的 work. Thank 你 so much. Thank 你 对于 the clarification-

Dr. Shanna Swan: 那's okay

安德鲁·休伯曼： ... truly, 和 对于 the work 那 led to 那.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 我们 have 这, thankfully, innate reflex to protect 我们的 young, as does most every species. Thank goodness. 和 我们 know 那 baby 皮肤 is 更多 absorbent than older 皮肤. 和 so there are literally laws in place 和 restrictions in place to make sure 那 这 stuff is minimized in young kids. 但 then 我们 sort of, 之后 age 12, 我们're kind of like, "Okay, well, it's a free-对于-all. It depends on 你的 budget, where 你 go." 和 so 我们 可以't rely on governing bodies to do 这.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 但 I think it's a useful conversation, 尤其是 given 你的 relationship to Scandinavia, which is a fun 一 to elaborate on. To illustrate some of the discrepancy between the US 和 Europe, what sorts of chemicals are banned in Europe, in food, in lotions, et cetera, 那 你're aware of, 那 are prominent here in the US? Maybe 那's a good filter to place some of 这 choice-making 通过.

Dr. Shanna Swan: Europe has had a policy called Reach, 和 under Reach, 你 have to show 那 a chemical is safe 之前 it's put 进入 the marketplace. So the way 我们的 系统 is here, is put in the marketplace, 和 then if somebody gets worried 关于 it, they 可能 do a 研究, they 可能 find harm. Remember how long it took me to find 那 phthalate connection? It was 10 years. 二 研究, 10 years, $10 million, by the way. So if 你're going to wait 对于 那, I don't know. Given the number of chemicals out there, 80,000 或 更多, forget it. So, I think the Reach policy of testing 之前 something's put in the market is making a big difference in Europe, 和 I think 那's 一 reason why they're much better off.

安德鲁·休伯曼： Are 那些 animal tests, 或 animal 和 human tests 那 they're doing over there?

Dr. Shanna Swan: Whatever defines safety. It depends on the chemical, it depends on what the product is. I 可以't answer 那 in general. 但-

安德鲁·休伯曼： So 那 可能 be a good avenue 对于 changing legislature here, right?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： To install something 相似的 to Reach.

Dr. Shanna Swan: Absolutely, 但 it's not going to happen, I don't think.

安德鲁·休伯曼： No?

Dr. Shanna Swan: No-

安德鲁·休伯曼： Why?

Dr. Shanna Swan: ... 因为 there's too many forces against 那. It's 非常 hard 对于 manufacturers to make changes. I'll give 你 一 example. So 你 know 那, 你 可能 not know, 但 应该 know, 那 phthalates are 非常 prevalent in the hospital setting. If 你 think of a tube, to dialysis, to chemotherapy, to IV, 那's all phthalates, right? 和 那's going 进入 你的 身体. 和 there was recently a bill passed in California 那 DEHP could not be in IV bags, which is fantastic. A success.

安德鲁·休伯曼： In the actual bag?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： The bags could not contain 这些 endocrine disruptors?

Dr. Shanna Swan: DEHP. Yes. DEHP specifically.

安德鲁·休伯曼： DEHP. Okay.

Dr. Shanna Swan: Diethylhexyl phthalate, the most anti-androgenic phthalate.

安德鲁·休伯曼： Got it.

Dr. Shanna Swan: So, 那 was a great step forward, 但 那's 一 chemical, right? In 一 product, 和 那 was a battle. So 你 see how hard it is to do 这. Extremely hard. There's a company, B. Braun, which makes hospital products, 和 they are 非常 forward-thinking, 和 they set up a factory in Florida to make alternative IV bags out of another product, polyolefin. 和 the problem is 那 我们're not sure 关于 the safety of polyolefin. So it gets 确实 difficult. 你 可以 say remove DEHP, 但 now 我们 scientists have to say, what does it mean 对于 a chemical to be safe? 和 我们 don't know 那. I don't mean to disillusion 你 和 你的 listeners-

安德鲁·休伯曼： No, 那's okay

Dr. Shanna Swan: ... 但 那's a huge challenge 那 我们're up against. 我们 know it's safer, 和 我们 know what the bad actors are, 和 我们 know the things 我们 don't want to be exposed to, 但 我们 have to be careful when 我们 think 关于 what do 我们 want to put in instead.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Does 那-- Yeah.

安德鲁·休伯曼： Yeah. Now I'm thinking 关于 这, a former president of Stanford, who also happened to be a family friend years ago, he since passed, Don Kennedy, when he retired as president of Stanford, my understanding is 那 he went 和 directed the FDA. 和 I was just thinking to myself, when did 这 happen? 因为 I know he was super 进入 health. He was an avid runner. He was 非常 fit well 进入 his 70s. Yeah, hip replacement, kept running, 或 maybe it was a knee replacement. I don't know. The guy was obsessed 与 health. 和 so I don't think 那 there's a lack of interest in health at the 水平 of things like the FDA. 但 there's clearly a problem. 和 I'm just trying to think of solutions, 和 it seems to all boil down to what 我们 可以 take control of in 我们的 home. Like when 我们 go to a restaurant, it's challenging to know what they're doing in the kitchen.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 和 at some point it becomes neurotic to-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 尽管 I know 人们 那 won't go to restaurants where they use seed oils. There's 这 whole new thing cropping up 关于 avoiding seed oils.

Dr. Shanna Swan: 对于 sure.

安德鲁·休伯曼： 但 maybe there are 更多 significant issues. Who knows? The seed oil crowd is pretty intense. 和 I like olive oil anyway, so I err to 那. 但 I think if 人们 are interested in limiting their exposure to 这些 endocrine disruptors, 一 of the key questions 那's going to come up again 和 again, 尤其是 in light of PCOS 和 sperm count, is 我们 可以't control what happened to us 期间 pregnancy.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 但 once 我们 have some sense of agency over what 我们 put 进入 我们的 身体 和 how 我们 put it 进入 我们的 身体, do 你 think 那 there's plasticity 和 resilience to 这 系统?

Dr. Shanna Swan: Mm-hmm.

安德鲁·休伯曼： So, God forbid, if somebody was exposed to a lot of 这些 things early on, by making changes-

Dr. Shanna Swan: No

安德鲁·休伯曼： ... 可以 they rescue themselves to any degree?

Dr. Shanna Swan: No.

安德鲁·休伯曼： No? So it's 确实 just dependent on what 你的 parents did.

Dr. Shanna Swan: Yes. 和 那's not to say 那 你的 own exposure cannot change things further 和 make things worse, 但 here's a fact. If a male's mother smokes when he's in the womb, then he has a, 这 is a Danish 研究 by the way, 50% reduction in sperm count.

安德鲁·休伯曼： If his mother smoked while he was in the womb.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： How much smoking are 我们 talking?

Dr. Shanna Swan: I don't know.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Don't remember. 但 the reason I bring 这 up is 因为 there's nothing he 可以 do to change 那. Okay? If he smokes as an adult, he has, I think, a 相似的 reduction in sperm count. He 可以 stop, 和 his sperm 会 be restored. He 可以 get his sperm health back. 但 whatever happened in the womb stays in the womb, if 你 会 .

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: It's developmental. It's going to be there 对于 life. 和 那's true 对于 the 大脑 as well. So, I think anybody who's thinking of conceiving a pregnancy 或 pregnant has a responsibility to 确实 learn how to 减少 their exposure, 因为 这些 things are, by the way, passed on 对于 several generations. It's 你的 child 和 你的 child's child, 因为 the germ cells 对于 你的 grandchild are going to be carried within 你的 child.

安德鲁·休伯曼： So germ cells are not germs as in infectious germs.

Dr. Shanna Swan: Right. Sorry.

安德鲁·休伯曼： It's the cells 那 会 produce the egg 和 sperm.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 那 germinate.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Hence the word germ.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: So it's a huge responsibility, 和 I think 人们 应该 take it 非常 seriously, 那 they're going to be affecting the health of subsequent generations. Some labs say it's seven generations. I don't know if 那's true. 但 certainly 三 generations are affected. 和 so I 应该 mention my book. 可以 I mention it?

安德鲁·休伯曼： Yeah, please. I'll mention it. Yeah. I believe I mentioned it in my introduction.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 但 yeah, please.

Dr. Shanna Swan: So in "Countdown," 二 words by the way, 因为 if 你 say countdown 一 word, 你 won't find it. 但 "Countdown," 我们 have 二 chapters on things 你 可以 do, 非常 practical things 你 可以 do, 和 also websites 你 可以 go to 和 links 你 可以 go to. Now, 这 came out a while ago, so '21, so there are many 更多 things now, 但 I think it's a good start.

安德鲁·休伯曼： Mm-hmm. How lonely are 你 in 这 expedition of identifying endocrine disruptors in food, in pesticides, in the sorts of things 你're talking 关于? Is there a whole field of 这, of excellent 人们, 或 are 你 a small team of 人们 那 are against the grain? I confess I don't know many 人们 doing the sorts of work 那 你're doing, 但 你're the most public-facing 和 prominent. 和 I guess my question is, is the NIH funding a lot of 这 sort of thing?

Dr. Shanna Swan: Absolutely. 我们're an army, 和 it's international. 和 there is now a global plastics treaty under negotiation, by the way, which is-

安德鲁·休伯曼： Tell us 关于 the plastics treaty. Yeah

Dr. Shanna Swan: ... 人们 are trying to create, get passed by various countries, an international plastics treaty. I don't want to talk a lot 关于 it. I'm not involved in 那 process. 但 in the process, 你 could see, if 你 looked 进入 there, hundreds of scientists 和 concerned citizens 和 activists 和 人们 in legislation who are working to Specifically on the chemicals in plastic. Now, plastic is 确实 a bad actor, 但 it is not the only bad actor. So I want to just mention 那 plastic is 确实 重要, 但 pesticides are not plastic, 和 so on. So there are many other classes 那 你 have to worry 关于, 但 certainly, controlling 我们的 exposure to plastic is huge. 和 你 asked 关于 scientists in 这 area. Yes, there's a huge amount of science going on in 这. 和 it's funded by NIH, 和 it's funded by the EU. 和 primarily, I think 那些 are the 二 funders, Scandinavia has funding within Scandinavian countries. So there's a lot of work 和 a lot of 非常 good 人们 working 确实 hard. 但 it's a huge problem, 和 it's been here since, well, plastic started to rise in popularity in 1950. So 我们 have 75 years to battle against, 和 it's not going down anytime soon.

安德鲁·休伯曼： Lifespan is increasing pretty significantly.

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Presumably in large part 因为 of the reduction in smoking-

Dr. Shanna Swan: 和 control of infectious diseases

安德鲁·休伯曼： ... 和 control of infectious diseases.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： 但 lifespan is definitely increasing, whereas the use of plastics has clearly 增加了. 和 so I guess 一 could argue 那 我们're living longer, 但 我们 are 更少 robust than 我们 were, 更少-

Dr. Shanna Swan: The-

安德鲁·休伯曼： ... reproductively competent. Is 那-

Dr. Shanna Swan: The 人们 那 are reflected in 那 longer lifespan were not necessarily exposed early in life, which is when it's most critical. So I was born in 1936. There was no plastic then. 和 there were other things, of course, 但 not as they are today. So I don't think 那 你 可以 make the inference 那 因为 我们're living longer, the growth of the plastics industry is somehow driving 那 longevity. Absolutely not. I think what it's driving is 降低 in fertility.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 what's happening is 那 the shift in populations is pretty dramatic. The pyramid used to be like 这. I'm making a triangle 与 my arms, showing 非常 few 人们 on top 和 a lot of 人们 on the bottom. 但 what's happening is 那 那's getting inverted, so 我们're getting 更多 和 更多 人们 on top 和 fewer 和 fewer 人们 on the bottom.

安德鲁·休伯曼： Birth rates are way down.

Dr. Shanna Swan: Birth rates are way down. 和 so 这 is an enormous problem 对于 societies 因为 the 人们 in 那 small support group at the bottom 可以't drive the society to support the large growth on top. 你 see what I'm saying?

安德鲁·休伯曼： Is 这 true in other countries as well?

Dr. Shanna Swan: Yes, absolutely. It's all over the world. 和 the decline in fertility, in my 心智, is probably 一 of the biggest challenges 我们're facing now, 因为 it's everywhere, it's 非常 acute, 和 there's only limited things 我们 可以 do to counter it. There's a wonderful website, it's by the World Bank, put out by the World Bank. It's called Fertility 数据. 和 if 你 go in there, 你 可以 see what is the fertility rate every year, 但 你 可以 plug in a country 或 a year 和 see what the fertility rate in each country in the world each year, 和 你 可以 see 那. 和 what 你 see is a decline.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 关于 the same rate as sperm decline, by the way. 关于 50% in 50 years. 和 the critical point 对于 fertility is 二. So what's 那 mean? 那's called replacement, 和 那's 二 人们 replace themselves 与 a total fertility rate of 二. Actually, 2.1 因为 你 have a little bit of loss. 但 2.1, 你're good to go as a society. When 你 fall below 那, 你're shrinking. 和 there are many countries in the world 那 are below 那, including the United States. 和 对于 example, the worst I've seen is actually South Korea, which is at 0.78.

安德鲁·休伯曼： Wow.

Dr. Shanna Swan: Japan is at 一.

安德鲁·休伯曼： Wow.

Dr. Shanna Swan: So large parts of the world are just not replacing themselves. 和 why 那 is is maybe another discussion, 或 我们 可以 talk 关于 it. I don't know if 你 want to go 进入 那. 但 it's not just sperm count, 对于 sure.

安德鲁·休伯曼： Along 那些 lines, let's talk 关于 egg count 和 quality.

Dr. Shanna Swan: Mm-hmm.

安德鲁·休伯曼： 你 mentioned the PCOS 结果 earlier. 之前 我们 were on mic, 你 mentioned an interesting 研究 那 你 did 关于 the use of electric blankets, 和 assessing whether 或 not the use of electric blankets had impacted egg number 或 quality in women, 和 the answer was?

Dr. Shanna Swan: Actually, what 我们 looked at in women, I'm sorry to correct 你, 但 it was the outcome of their pregnancy, their fertility, 和 if they got pregnant, how did 那 turn out? 但-

安德鲁·休伯曼： Excuse me. Sorry.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Thank 你 对于 那 clarification.

Dr. Shanna Swan: 但 I'm sure there'd be a lot of other 研究 那 have looked at 那. I just have been away 从 那 field 对于 a long time. 但 so far, I don't see convincing 证据 那 the use of cell phones 或 other exposures to electromagnetic radiation are affecting 我们的 pregnancies 和 我们的 fertility. 那's not to say it's not happening, 但 I have not looked at it, 和 I don't like to make statements 关于 things I haven't looked at.

安德鲁·休伯曼： My understanding of the cell phone 数据 对于 sperm count 和 motility, AKA quality, is I discussed a meta-analysis covering 这 on the podcast previously, is 那 there are some 热 effects of cell phone use 和 keeping the phone in the pocket 那 may I want to be careful here, impact sperm count 和 motility quality. 但 direct effects of EMFs on sperm, there's no 证据 那 it is disrupting sperm, at least to my knowledge.

Dr. Shanna Swan: I honestly have to say, just going to say I don't know. 但 I do know 那 热 is related to fertility 和 sperm count.

安德鲁·休伯曼： Right.

Dr. Shanna Swan: 和 你 可以 look at the birth rates as a function of the month of conception, 和 你 可以 see 那, 对于 example, in warm months, in warm climates, there's 更少.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: Yeah. So 热 does play a role-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... 但 how much 那's tied to cell phone use, I think 那's something 那's now under investigation by a lot of groups, 和 我们'll see what they find.

安德鲁·休伯曼： Yeah, the 数据 on sitting 更多 than a few 小时 a 天, on having legs 那 are 非常 large as a consequence of obesity, 或 even just legs 那 are large, heating the scrotum, 那些 数据 are fairly, I 会 say, solid, in terms of the relationship to 减少 sperm count. 热 is not good 对于 sperm, which is why the scrotum has the features 那 it does-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... to move the testicles further 或 closer to the 身体. Getting back to egg count 和 quality, there's some 证据 那 girls are entering puberty earlier, 但 那 women are also undergoing perimenopause 和 menopause earlier.

Dr. Shanna Swan: Earlier, 那's right.

安德鲁·休伯曼： Do 我们 know what 那 is the consequence of?

Dr. Shanna Swan: There are several new papers, actually, on the menopausal age showing relation to a number of chemicals, 但 I 可以't quote them to 你 right now. I don't remember which class it was 那 they looked at, 但 I think 那's right. I think there is growing 证据 那 earlier, it's also called premature ovarian failure-

安德鲁·休伯曼： Mm

Dr. Shanna Swan: ... so 那 women are just not producing the eggs as long as they used to. Yeah. 但 I just want to say something 关于 the fertility. 可以 我们 go back to fertility?

安德鲁·休伯曼： Please.

Dr. Shanna Swan: So when 这 comes up, 和 I'm sure 你've seen the literature, there's a lot of literature on 这 那 say fertility is going down, fewer children are being born. A, 人们 say, well, 那's a good thing 因为 it's 更少 of a load on the planet, which is another discussion. 和 then they say, well, 这 is due to choice, 那 人们 are choosing to have fewer children, 和 they're choosing to delay childbearing till they're no longer as fertile. They're using 更多 contraception. Women are 更多 educated. They're entering the workforce. All of 这些 social factors are given as the reason 对于 decline in fertility. 和 I just need to point out whenever I hear 这, 那 it's not just human fertility 那's declining. The number of species 那 are becoming extinct is increasing rapidly, 和 there have been, 对于 at least 40 years, 证据 那 那些 pesticides 那 affect us are affecting animals as well. 和 so the decline in fertility in non-human species cannot be attributed to delayed childbearing 或 use of contraception 或 entering the workforce.

安德鲁·休伯曼： 或 rent crisis, right?

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 和 it's interesting 因为 我们 usually hear 首先 关于 species 那 are 关于 to go extinct, 那 are badly endangered. I don't know what the proper language is, 但 关于 to go extinct. Like the Florida panther.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 或 我们 hear 那 there are 这些 species of like there's a 非常 small subset of them left. The black-footed ferrets in Montana, I think 一 ferret, his name is Scarface, sired something like 300 litters 那 then led to the-- Eventually they started outbreeding, 因为 if 你 do too much inbreeding, obviously it's not good. 但 then they were able to at least partially recover, maybe fully recover 那些 populations. 和 人们 forget the domino effect of 这些 ecosystems when 一 species is compromised. Like when the black-footed ferrets, I know it 可能 sound kind of silly, 但 were compromised in terms of their populations, the prairie dog population went up, the grasses were getting eaten far 更多, 和 then there's all 这些 downstream consequences-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... on bugs 和-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... 和 I'm not an expert in 这-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 但 一 doesn't have to be an expert to understand, 你 move 一 pin here, 和 the whole web moves.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 或 你 move 一 node, 和 the whole web reconfigures. 和 那's what nature has been doing 对于 millions of years, right? 但 at some point, it is conceivable, no pun intended, 那 我们 are going to be the species on the endangered species list, right?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： 那's not like an outrageous sci-fi movie.

Dr. Shanna Swan: No. 那's right.

安德鲁·休伯曼： At some point, humans 可能 be added to the endangered species list.

Dr. Shanna Swan: 与 the exception 那 我们're 非常 clever, 和 so 我们've found a lot of ways to do medically assisted conception.

安德鲁·休伯曼： Right. ICSI, the literally gentle grabbing of 一 sperm 和 forcing it to fertilize the egg, is something 我们've covered on 这 podcast in 我们的 fertility episode 与 Natalie Crawford 和 a solo episode 那 I did. There are questions 那 人们 have, reasonable questions 关于 whether 或 not the offspring of 那些 types of scenarios are the same as the-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... genetic probability experiment, as 你 mentioned 之前, of having 200 million sperm 和 then letting nature select the 一 那 is most-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... robust in 那 environment.

Dr. Shanna Swan: Yeah. 和 the number of technologies is increasing. 我们're a 非常 clever species.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 对于 example, I don't know if 你've heard of gametogenesis.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: So it is now 可能 to create an embryo 从 a 皮肤 cell. A 皮肤 cell 可以 produce a sperm cell 和 an egg cell, 和 你 可以-

安德鲁·休伯曼： So 你 give it the right transcription factors, 和 你 可以-

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 你 可以-

Dr. Shanna Swan: So 这 is kind of interesting-

安德鲁·休伯曼： 那's wild

Dr. Shanna Swan: ... exciting, 和 scary, right?

安德鲁·休伯曼： 这 is like the, what is it? I think the vultures, the females, there's some way in which 二 female vultures 或 maybe a single female vulture 可以 create offspring in the absence of a male. There's also a 三-party IVF, I don't know if 你're aware of 这, where 这 was developed where there's a mitochondrial disease.

Dr. Shanna Swan: Mm.

安德鲁·休伯曼： 你 可以 take the 二 eggs, 一 从 the intended mother. 你 take the nucleus, so 你 get the DNA.

Dr. Shanna Swan: Mm.

安德鲁·休伯曼： 你 put it 进入-

Dr. Shanna Swan: Uh-huh

安德鲁·休伯曼： ... an egg of somebody 那 where the DNA has been removed-

Dr. Shanna Swan: Ah

安德鲁·休伯曼： ... 但 where the spindles, which are rich 与 mitochondria, are 从 通常 a much younger-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... host, 和 then 你 use a sperm. So it's actually 三 parents. It's the spindle of 一 mom, the DNA of another mom-

Dr. Shanna Swan: I haven't heard of 那

安德鲁·休伯曼： ... 和 a sperm. They do 这 in the UK 对于 mitochondrial disease.

Dr. Shanna Swan: Wow.

安德鲁·休伯曼： It's still illegal in the United States-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... as far as I understand, 和 it's done in other countries. 和 in theory-

Dr. Shanna Swan: Legal issues must be

安德鲁·休伯曼： Yeah, 但 in theory, 这 会 allow women of any age, provided they still have eggs, to have their DNA propagated forward 因为 the DNA-

Dr. Shanna Swan: Right

安德鲁·休伯曼： ... 可以 be put 进入 a younger egg 那 has the spindle quality 那 allows 对于 the production of 更多 cells.

Dr. Shanna Swan: So-

安德鲁·休伯曼： 这 可以 和 has been done in humans.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yeah.

Dr. Shanna Swan: 你 和 I won't think of all the things 那 会 be developed in the next 10, 20 years-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... to meet the challenge of declining fertility by ordinary conception. I think 那's how 我们're going to solve 这 problem 对于 us. 我们're going to just be smarter 和 smarter 关于-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... how to do medically assisted-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... conception. 和 then the question is going to be, 和 it'll take time to know 这, is whether there are adverse effects in the offspring.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: It's a little tricky 因为, 对于 example, if 你 use the sperm of an infertile couple 和 let's say the son is subfertile, 那's born 那 way.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 但 你 do it in a test tube 或 whatever. 和 then 你 可以 say, well, maybe 那's 因为 the father was infertile, 和 he's got inheritance 从 the father 从 那. 你 know what I'm saying? So 你 可以't know if 你 see an adverse effect in an offspring, 你 have to be 非常 careful 那 it's not something 那 they've gotten 因为 of problems 那 led the couple to seek assisted reproduction. 你 follow me?

安德鲁·休伯曼： Yep.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Yep.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Super challenging, fascinating problem. So in anticipation of 这 sit-down together, I put a question out on X, formerly known as Twitter. I let 人们 know 那 I was hosting an expert in endocrine disruptors, in phthalates 和 pesticides, reproductive implications, et cetera. 和 I asked 对于 questions. 和 they came up 与 a huge number of excellent questions, many of which 你've already answered.

Dr. Shanna Swan: Mm.

安德鲁·休伯曼： Things like is tap 水 safe? What 可以 我们 do to 我们的 tap 水? 你 mentioned 你 distill 水. My understanding is 那 reverse osmosis, provided there's remineralization, excuse me, difficult word to say, 可以 also be effective, et cetera.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： There were a lot of questions 关于 cosmetics 和 laundry detergents. I don't know if 我们 discussed laundry detergents. What do 你 use in terms of laundry detergent? 或 那 is presumably 一 可以 find-

Dr. Shanna Swan: I don't even remember.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Don't go by my products.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: 对于 一 thing, I'm not going to be pregnant anytime soon. No.

安德鲁·休伯曼： I believe there are some solutions related to the, like instead of bleach, 人们 可以 use hydrogen peroxide.

Dr. Shanna Swan: I 可以't speak 关于 具体的 products, actually.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: I 可以 tell 你 who 可以. 你 可能 like to talk to her. So 你 remember I mentioned Million Marker?

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: The company 那 did the inventory? Well, they are a company. Look at Million Marker. I think 你'd be interested.

安德鲁·休伯曼： Okay.

Dr. Shanna Swan: Yeah.

安德鲁·休伯曼： Great.

Dr. Shanna Swan: 和 the person who runs 那, Jenna Hua, is a Chinese American 和 a friend of mine, 和 我们're going to be writing a grant together. 和 she participated in the film, so 我们的 参与者 sent their... If 你 go to Million Marker, 你 log on, 和 if 你 agree to pay whatever it is, $100, $199, I think. 你 send 你的 urine in.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: They give 你 a kit, 你 send 你的 urine in, 和 they test it 对于 all 这些 things in 你的 urine, so 你 know what's in 你的 身体. 你 可能 want to think 关于 it. 可能 be interesting.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 then if 你 pay another $100, I think 你 get 这 counseling 和 so on, blah, blah. So 你 可以 see the 不同的 水平. 但 she knows all 关于 products. I don't know 关于 product 因为 it's a moving target.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 also, I don't like to talk 关于 product names 因为 it sounds like I'm endorsing them.

安德鲁·休伯曼： Yeah. Right. 和 我们 won't expect 你 to give product names, 和 I'll follow 你的 recommendation 那 你 just gave. Somebody asked 关于 food dyes, just generally the dyes in foods. I saw an incredible 研究 recently-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 那 "Science Magazine" covered. So "Science Magazine," 非常 reputable, of course. Yellow number five, I forget what the precise name is-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... 但 the thing 那 makes Cheetos 确实 bright-

Dr. Shanna Swan: Oh

安德鲁·休伯曼： ... they put it on the bellies of adult mice, 和 it literally makes them translucent.

Dr. Shanna Swan: Oh yeah, I saw 那

安德鲁·休伯曼： 你 可以 see the organs.

Dr. Shanna Swan: I saw 那.

安德鲁·休伯曼： It's wild.

Dr. Shanna Swan: Super scary.

安德鲁·休伯曼： It's so scary. I sent it to Rogan, 和 he was like, "Whoa." His version of whoa.

Dr. Shanna Swan: Mm-hmm.

安德鲁·休伯曼： I also said, "Whoa."

Dr. Shanna Swan: He probably said, "Holy shit," right?

安德鲁·休伯曼： No, he said-

Dr. Shanna Swan: 或 worse.

安德鲁·休伯曼： No. I'm not going to say what it said. He didn't curse. There were a number of questions 关于 household items. Again, 我们're not looking 对于 具体的 products, 但 对于 instance, soaps, 身体 wash, cleaning sprays, floor cleaners, laundry-related cleaners, do any 或 all of 这些 contain endocrine disruptors-

Dr. Shanna Swan: Yes

安德鲁·休伯曼： ... unless 一 is careful to find the ones 那 don't?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Okay. Receipts. How serious is it? 应该 我们 be concerned 关于 the BPAs 和 other endocrine disruptors on receipts?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： So-

Dr. Shanna Swan: 和 my suggestion is just ask 对于 an electronic receipt.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 和 then 你 don't have to deal 与 it, yeah.

安德鲁·休伯曼： Mm-hmm.

Dr. Shanna Swan: 但 they're definitely absorbed 进入 你的 身体.

安德鲁·休伯曼： Any impact of endocrine disruptors of the sort 我们've talked 关于 today on the thyroid 系统?

Dr. Shanna Swan: Yes.

安德鲁·休伯曼： Presumably in the bad direction, not in-

Dr. Shanna Swan: Yeah. 这 is an interesting point. Let me just say another word 关于 it. There was an ongoing 研究 in the Faroe Islands off Denmark, 和 they studied PFAS chemicals 和 showed 那 人们 who fished there, there were fisher 人们, 和 they ate the fish, 和 they were getting high 水平 of PFAS in their 身体, 和 had, 和 这 is published, effects on their 免疫 response. So my concern, 和 I don't know if anyone's looked at 这, is given everyone's vaccination is 我们的 response to vaccination now altered by 这些 chemicals? I don't know, 但 I think it's a 确实 interesting question. 但 there is a whole field of the effect of 这些 chemicals on the thyroid 系统, 和 there's a lot of 证据 那 it's adverse.

安德鲁·休伯曼： 可以 这些 endocrine disruptors be detoxed 从 the 身体? Is there anything 那 我们 可以 do? What's the quickest ways? Things like 出汗. Are there ways to 改善 liver clearance of 这些 endocrine disruptors?

Dr. Shanna Swan: The answer to 那 depends on the class of chemicals. So the chemicals 那 are 水 soluble-

安德鲁·休伯曼： Mm-hmm

Dr. Shanna Swan: ... in particular, the phthalates 和 the bisphenols, leave the 身体 in a matter of 小时. 你 don't have to do anything. 你 just have to stop taking them in, right? The forever chemicals, the PFAS chemicals, pesticides are... So it has to do 与 how they're handled by the 身体. If they're 水 soluble, 你 pee them out. If they're fat soluble, they're going to be 大约 对于 a long time. So it just depends on the chemical structure of the compound.

安德鲁·休伯曼： There was a question 关于 non-stick pans. 你 covered 那 earlier. If someone had to pick between non-stick coated pans versus seasoned iron pans.

Dr. Shanna Swan: No question, iron. There's no risk associated 与 seasoned iron pans.

安德鲁·休伯曼： A number of other questions, such as, why does Europe have such 更多 stringent laws, et cetera? Lots of questions 关于 atrazine, questions 关于 ointments 和 fragrances 你've covered. 和 I must say 那 as I scroll 通过 这些 hundreds of questions-

Dr. Shanna Swan: Yeah

安德鲁·休伯曼： ... if not 更多, 你've done an amazing job at clarifying 对于 us what's known, what is not known, 和 本质上 where it's a probably 应该 avoid, definitely avoid, 和 look, 我们 just don't know.

Dr. Shanna Swan: Right.

安德鲁·休伯曼： 和-

Dr. Shanna Swan: Well, I have to distinguish between 我们 just don't know 和 I just don't know. There are many things 那 I don't know.

安德鲁·休伯曼： Sure.

Dr. Shanna Swan: Right?

安德鲁·休伯曼： Sure.

Dr. Shanna Swan: It's a huge field, so-

安德鲁·休伯曼： Right

Dr. Shanna Swan: ... maybe ask the question of ChatGPT.

安德鲁·休伯曼： Mm-hmm. Yeah. 我们'll be certain to ask ChatGPT, 和 我们 会 be certain to ask other experts in 这些 areas. 但 I just want to make 非常 clear, I 和 everyone listening 和 watching truly appreciate the work 那 你've been doing-

Dr. Shanna Swan: Thank 你

安德鲁·休伯曼： ... in 这 area 对于-

Dr. Shanna Swan: Sure

安德鲁·休伯曼： ... a number of years. 我们're so grateful 那 你 took 那 airline flight 与 这 chemist 那 你 mentioned, 那 你 stored the urine of 那些 pregnant women, 那 你 analyzed it, 和 那 你've gone down 这 path of exploring things 那 are 确实 disruptive to 我们的 health, 和 potentially to the existence of 我们的 species. As 我们 talked 关于 earlier, there is the possibility 那 我们 go extinct, not 因为 of a meteor, 但 因为 我们 fail to replace ourselves, 和 那 我们 fail to replace ourselves 因为 我们 destroy 我们的 biological ability to replace ourselves. I think it's hard 对于 人们 to internalize 那 非常 real possibility 因为 我们 feel ourselves sitting in traffic 与 thousands of other 人们, 和 go, "There's too many 人们," 这 kind of thing. 但 want to thank 你 对于 the work 那 你've been doing 和 continue to do, 对于 你的 willingness to write books 和 to educate the public on podcasts like 这 和 others. 因为 这些 are topics 那 are pretty emotionally loaded 对于 人们. I don't think anything gets 人们 quite as inflamed as the idea 那 what they've been ingesting 和 exposed to, 尤其是 in terms of consumables 那 they've spent their hard-earned money on, have been-

Dr. Shanna Swan: Harming them

安德鲁·休伯曼： ... harming them 和 their offspring 和 generations to follow. 那 there's something 那 确实 lands deep in 那 way. 但 你've also offered us a lot of possibility 和 a sense of agency over 这些 things. 和 I love 那 你 weave 你的 math 和 statistics 和 probability theory background 进入 all of 这, 因为 what comes 通过 is intense curiosity, intense rigor, 和 a real desire to do good. So thank 你 so much 对于 joining us, 和 please come back again as 你 make 更多 discoveries.

Dr. Shanna Swan: I'd love to.

安德鲁·休伯曼： Thank 你.

Dr. Shanna Swan: It's been 确实 fun.

安德鲁·休伯曼： Thank 你 对于 joining me 对于 today's discussion 与 Dr. Shanna Swan. To learn 更多 关于 her work 和 to find a link to her excellent books on 这些 topics, please see the links in the show note captions. Also, I 应该 mention 那 if 你're interested in learning 更多 关于 microplastics 和 endocrine disruptors, I did a solo episode of the Huberman Lab 播客 on 那 topic, 和 那 is also linked in the show note captions. If 你're learning 从 和/或 enjoying 这 podcast, please subscribe to 我们的 YouTube channel. 那's a terrific zero-cost way to support us. In addition, please follow the podcast on both Spotify 和 Apple by clicking follow on Spotify 和 Apple. 和 on both Spotify 和 Apple, 你 可以 leave us up to a five-star review. Please also check out the sponsors mentioned at the beginning 和 throughout today's episode. 那's the best way to support 这 podcast. Also, if 你 have any questions 对于 me 或 comments 关于 the podcast 或 guests 或 topics 那 你'd like me to consider 对于 the Huberman Lab 播客, please put 那些 in the comments section on YouTube. I do read all the comments. 对于 那些 of 你 那 haven't heard, I have a new book coming out. It's my 非常 首先 book. It's entitled "方案: An Operating Manual 对于 the Human 身体." 这 is a book 那 I've been working on 对于 更多 than five years, 和 那's based on 更多 than 30 years of 研究 和 experience. 和 it covers 方案 对于 everything 从 sleep to 运动 to 压力 control, 方案 related to 专注 和 motivation, 和 of course, I provide the scientific substantiation 对于 the 方案 那 are included. The book is now available by presale at protocolsbook.com. There 你 可以 find links to various vendors. 你 可以 pick the 一 那 你 like best. Again, the book is called "方案: An Operating Manual 对于 the Human 身体." If 你're not already following me on social media, I am Huberman Lab on all social media platforms. So 那's Instagram, X, formerly known as Twitter, Threads, Facebook, 和 LinkedIn. 和 on all 那些 social media platforms, I discuss science 和 science-related tools, some of which overlap 与 the content of the Huberman Lab 播客, 但 much of which is distinct 从 the content covered on the Huberman Lab 播客. Again, 那's Huberman Lab on all social media platforms. 和 if 你 haven't already subscribed to 我们的 Neural Network Newsletter, 我们的 Neural Network Newsletter is a zero-cost monthly newsletter 那 includes podcast summaries, as well as 方案 in the form of brief 一 to 三-page PDFs. 这些 方案 cover things like 主动冷暴露, deliberate 热 exposure, how to optimize 你的 多巴胺, how to 改善 你的 sleep, all available at zero cost. To access 这些 newsletters, simply go to hubermanlab.com, go to the top right corner menu, scroll down to Newsletter, 和 enter 你的 email. 和 I 应该 mention 那 我们 do not share 你的 email 与 anybody. Thank 你 once again 对于 joining me 对于 today's discussion 与 Dr. Shanna Swan. 和 last 但 certainly not least, thank 你 对于 你的 interest in science.