The Art of Manliness - How Testosterone Makes Men, Men

00:00:00.000 Brett McKay here, and welcome to another edition of the Art of Manliness podcast.

00:00:11.040 What creates the differences between the sexes? 1.00

00:00:13.920 Now, many would point to culture, and my guest today would agree that culture certainly shapes

00:00:17.740 us, but she'd also argue that at the core of the divergence of the sexes, and in particular

00:00:22.020 of how men think and behave, is one powerful hormone, testosterone.

00:00:26.560 Her name is Dr. Carol Hooven, and she's a Harvard biologist and the author of Tea, the Story

00:00:30.920 of Testosterone, the Hormone That Dominates and Divides Us.

00:00:33.940 Today on the show, Carol explains the arguments that are made against testosterone's influence

00:00:37.480 on shaping men into men, and why she doesn't think they hold water.

00:00:40.780 She then impacts the argument for how testosterone does function as the driving force in sex differences,

00:00:45.160 and how it fundamentally shapes the bodies and minds of males.

00:00:47.960 We delve into where tea is made, how much of it men have compared to women, and what historical

00:00:52.360 cases of castration tell us about the centrality of testosterone in male development.

00:00:56.560 We then discuss how tea shapes males starting in the womb and going into puberty and beyond

00:01:00.600 before turning to its influence in athletic performance, and we enter a conversation with

00:01:04.380 Carol's impassioned plea for celebrating what's great about men.

00:01:08.400 After the show's over, check out our show notes at aom.is slash tea.

00:01:23.460 Carol Hooven, welcome to the show.

00:01:24.740 Thanks so much for having me, Brett.

00:01:27.360 So you've got a book called Tea, the Story of Testosterone, the Hormone That Dominates

00:01:31.340 and Divides Us.

00:01:32.600 So you have spent your career studying the physiological and psychological effects of testosterone on

00:01:39.060 humans and other animals.

00:01:40.480 How'd that happen?

00:01:42.800 Okay.

00:01:44.120 Wow.

00:01:44.680 I don't know where to start.

00:01:45.720 I guess I could start.

00:01:47.160 I'll just start by saying when I graduated from college, I had no idea what I wanted to

00:01:52.260 do, I just sort of got a regular job.

00:01:55.740 I did that for 10 years.

00:01:56.980 And then I decided that I wanted to go work with Richard Wrangham, who I know you've had

00:02:01.820 on the show before.

00:02:02.820 And the reason I wanted to do that is because I had been taking classes and reading books

00:02:08.120 and just trying to, and traveling and trying to figure out what I really wanted to do when

00:02:12.040 I grew up.

00:02:13.460 And I read this book by Richard Wrangham called Demonic Males.

00:02:17.860 And I had really been focusing in on understanding human behavior and I'd gotten really interested

00:02:23.740 in neurobiology.

00:02:25.180 Then I discovered genetics and evolution and got really interested in that.

00:02:29.260 And then I read Richard's book, which used research on non-human primates, primarily chimps,

00:02:37.200 as a way to understand the evolutionary and genetic origins of human behavior, particularly

00:02:44.160 aggression.

00:02:45.360 And I thought that was fascinating.

00:02:46.980 And I thought that was something that I might be able to actually do, especially because

00:02:51.100 Richard was at Harvard at the time.

00:02:53.160 And so I quit my job and applied to the Harvard graduate program and got rejected because I had

00:03:00.900 no relevant experience.

00:03:03.080 And then I really bugged Richard and some other people in the department.

00:03:08.780 And I was like, look, I already quit my job.

00:03:10.700 This is what I want to do.

00:03:12.820 And eventually, because I was persistent and enthusiastic, not because I had any special

00:03:17.740 expertise, I have to say, Richard gave me an opportunity to go out to Uganda and study

00:03:23.560 chimps for a year.

00:03:24.580 I ended up getting evacuated because there was a lot of really awful violence and political

00:03:29.000 upheaval around Uganda in that region of Africa at the time.

00:03:33.560 So I only spent eight months out there.

00:03:35.540 But long story short, it was spending eight months in the jungle with chimpanzees surrounded

00:03:42.520 by a lot of actual human aggression and violence that got me really interested ultimately in

00:03:50.240 testosterone because anyone who goes and spends time with chimps can see that the sex differences

00:03:59.100 in the chimpanzees in so many ways mirror sex differences in humans, just in these very

00:04:05.320 broad patterns of status and hierarchy obsession among the males competing largely for food and

00:04:15.840 the right to have sex with the females who are in estrus, who can get pregnant. 0.98

00:04:21.200 So there's a lot of aggression.

00:04:22.540 There's a lot of status obsession in the males.

00:04:25.840 They're also capable, you know, like humans are, of being kind and nurturing and warm and

00:04:33.220 family-oriented in a way.

00:04:35.840 And the females, on the other hand, I never saw, although it does happen, I never saw any instances

00:04:42.060 of female physical aggression.

00:04:43.680 I saw it every single day among the males.

00:04:48.200 And so that was just this very pronounced sex difference where there was a lot of nurturing

00:04:53.220 and caregiving among the females, just much more peaceful overall on, you know, all of this 0.57

00:04:59.800 is on average and they don't have any human culture. 0.55

00:05:03.520 So there was nobody who was going to be able to convince me after that experience that these

00:05:08.120 similar patterns of sex differences in humans are primarily due to human culture.

00:05:13.200 They're not, they're molded by human culture.

00:05:16.720 The way they're expressed, you know, is heavily dependent on human culture, but the evolutionary

00:05:20.880 and genetic origins are, you know, in us, we're born that way.

00:05:26.920 And so that's why I got interested in testosterone because there's no more powerful way of explaining

00:05:31.380 human sex differences, which are, you know, male behavior in particular is a really important

00:05:37.940 aspect of our lives.

00:05:40.720 Yeah.

00:05:40.860 One of the goals of your book is to push back some of these popular arguments out there

00:05:44.920 that testosterone really doesn't influence differences between the sexes.

00:05:48.960 There's lots of them.

00:05:49.780 I mean, can you briefly summarize the arguments against T's influences on sex differences?

00:05:53.460 Like if it's not testosterone, what are they saying is causing the sex differences?

00:05:56.980 Right.

00:05:57.880 I've been asked this before and I admit I do find it challenging because, but, but it's

00:06:02.280 a really good exercise.

00:06:03.280 And I try to do this in the book, which is to entertain the best argument from the opposition.

00:06:09.700 So most critics, except for the most extreme ones will acknowledge that the physical differences

00:06:17.700 basically from the neck down are due to testosterone.

00:06:23.340 So it really, you have to be kind of a nut job to deny that male size and strength overall,

00:06:32.560 although there are nut jobs who are getting a lot of press, unfortunately, but that's just

00:06:37.980 really would be incredibly far-fetched to try to deny the science that testosterone at least

00:06:43.480 explains the secondary sex differences in humans.

00:06:47.540 So that's height, muscle mass, you know, fat distribution, body hair, those kinds of

00:06:54.940 things.

00:06:55.180 So most critics will acknowledge that testosterone is responsible for those physical differences.

00:07:00.380 More reasonable critics, and I think, you know, this can play a really useful role in

00:07:05.380 the science of testosterone and sex differences.

00:07:08.340 Most other critics deny that testosterone has any important effects on the brain and thus behavior,

00:07:15.280 and that it is not ultimately sort of the most powerful driving force in those sex differences

00:07:21.820 that I just talked about.

00:07:23.080 So the largest sex differences that exist, and this is not my view, this is fact, I'm 0.99

00:07:27.740 not talking about the cause, I'm just talking about the observation, are in sexual psychology

00:07:33.300 and behavior and physical aggression.

00:07:36.260 So those are huge, consistent with non-human animals.

00:07:39.320 We see them across ages, not the sex part, but across cultures, you know, they're just

00:07:45.320 incredibly pervasive.

00:07:47.040 And so those sex differences exist, but the question is, does testosterone influence the

00:07:53.240 brain and behavior in ways that promote increased physical aggression in males and increased desire

00:08:01.640 for variety and number of sexual partners?

00:08:04.220 So those are the biggest sex differences, and those are the ones I really focus on in the 0.80

00:08:07.380 book because there's so much clear evidence that testosterone in the early developmental

00:08:12.980 period, like around, you know, prenatally and directly postnatally, and then in puberty

00:08:18.460 and beyond, that those differences in exposure to that hormone and how it acts coordinates

00:08:24.680 the body, the physical adaptations of size and strength with psychological adaptations that

00:08:32.300 enable male animals, including humans, to take advantage of their larger body size and the

00:08:38.140 fact that they have sperm in a penis, that they have to be motivated to want to get that

00:08:42.960 sperm into the female reproductive tract. 0.99

00:08:45.060 And to do that, especially over human evolutionary history, there had to be physical competition

00:08:50.540 with other males for status or for the resources they need to acquire high status, which enable,

00:08:56.320 you know, and that could be territory.

00:08:57.480 Now it's, a lot of that is money and professional status.

00:09:02.600 But doing all of that increases the chances that males will be able to have a higher number

00:09:09.080 of sex partners, ultimately.

00:09:11.260 I mean, and there's different strategies that males can use, and we can get into that. 0.98

00:09:15.280 So it might not be an increased number of sex partners, but it might be using one's body

00:09:21.300 and having the psychology to want to use one's body or even just one's sort of competitiveness

00:09:27.180 and desire to elevate one's status.

00:09:31.600 That could result in the acquisition of a high quality mate, where if you mate with that 0.99

00:09:36.900 single female for life, you could do very well reproductively. 1.00

00:09:41.020 It doesn't mean that you have to have 10 kids, but it means you have to acquire that mate and 0.98

00:09:46.120 have sex with her. 0.98

00:09:47.840 So the adaptation is not the male desire necessarily for children. 0.98

00:09:53.320 It's the desire to either partner with one or a few mates and be a good partner or play

00:09:59.640 the field and have many different partners.

00:10:02.140 There's many different strategies, but sorry, this is a long answer.

00:10:04.960 But the idea is that testosterone coordinates the psychological adaptations with the physical

00:10:11.800 adaptations.

00:10:12.980 And I should just get back to the critics because I've gotten off the topic here.

00:10:16.120 But the critics are, to me, bizarrely denying that they'll accept that testosterone acts

00:10:22.620 on the body, but then are denying that it acts on the brain because they want to assert and

00:10:27.860 they do assert that because we live in a gendered society, the default assumption should be that 0.98

00:10:33.700 the sex differences that we observe are due to social and cultural influences.

00:10:38.260 But this just doesn't make sense from a scientific and evolutionary point of view.

00:10:43.760 The default assumption is that we are like all of these other animals where testosterone does

00:10:50.060 these very same things in males.

00:10:51.800 It's not a coincidence that it does the same thing in humans.

00:10:56.000 It's just that our culture can exacerbate those differences.

00:11:00.260 They can minimize, the culture can minimize or kind of enlarge those differences or just

00:11:05.060 budge the expression around.

00:11:06.200 So it's always gene, culture, interactions.

00:11:10.080 Why do you think the critics are so reluctant to embrace the fact that T influences not just

00:11:15.080 the body, but the mind?

00:11:16.140 Like what is like the apprehension?

00:11:18.640 Yeah, I think it's based on fear, which should not be playing a role in science and our efforts

00:11:27.400 to understand reality.

00:11:28.740 So even if the fear was true, if the fear was based in reality, so suppose the fear is that,

00:11:37.120 well, if men are dominant to women and have power, commit rape, cheat on their wives, if that's 0.89

00:11:45.040 because of something in their genes, if that's because their genes code for high levels of

00:11:50.540 testosterone and testosterone promotes these behaviors, the fear might be, well, then there's

00:11:55.580 nothing we can do about it.

00:11:57.500 Then we're stuck with bad male behavior and it justifies bad male behavior because it's

00:12:03.680 natural.

00:12:04.400 That's called the naturalistic fallacy, by the way.

00:12:06.860 The idea that what is found in nature is good.

00:12:09.920 You know, anyone can see in two seconds that there's plenty of things that are natural,

00:12:14.200 like malaria, that are terrible.

00:12:17.080 So that's just a bad argument.

00:12:19.480 And there's also plenty of evidence that we are definitely, that's biological, the idea of

00:12:24.900 biological determinism, that if something is in our genes, it's immutable and we're stuck

00:12:29.480 with it and we have to accept it.

00:12:30.720 Of course, that's not true either.

00:12:32.640 And all you have to do is look around the world at different cultures and different societies

00:12:38.460 and see what the differences in, say, the rates of murder are.

00:12:44.180 Because males commit across the world about 95 to 98% of all murders. 0.69

00:12:51.100 But in some cultures, the sex difference in the murder rate and the murder rate itself

00:12:56.220 is incredibly low.

00:12:58.020 And I always use Singapore as an example because it's extremely safe.

00:13:02.900 People, especially women, can walk around feeling safe because the sexual assault is incredibly 0.96

00:13:09.340 low.

00:13:10.380 You know, physical aggression committed by males in general is extremely low.

00:13:14.740 And that's because of their culture and harsh penalties for those crimes.

00:13:18.180 So, and that's just one example.

00:13:21.220 And we know that there are examples on the other end.

00:13:23.300 Like I was just talking to a grad student in my department who is from India and he was,

00:13:30.060 and I, you know, know the data on India, but sexual assault is rampant because it hasn't

00:13:35.860 been taken seriously in India by the government there and the, you know, you can get away with 0.97

00:13:41.600 it.

00:13:41.980 And so men, if you can get away with it, men are going to do it and they do.

00:13:45.260 So the idea is that genes and testosterone sort of lower the bar for the expression of

00:13:53.020 those behaviors in the right environmental circumstances.

00:13:57.020 But that doesn't mean that the environment can't shape heavily the expression of those

00:14:03.000 behaviors, right?

00:14:03.920 So males are definitely more inclined to those behaviors, but we know that there's all kinds

00:14:08.360 of things we can do to tamp down the expression of those behaviors.

00:14:12.040 And that's clear from just even looking across cultures or even across time and how we've

00:14:17.120 changed over time.

00:14:18.160 Our genes haven't changed, but the laws have and that social norms have.

00:14:22.360 Okay.

00:14:22.380 Let's dig into the basics of testosterone.

00:14:25.040 I think everyone has a general idea what it is.

00:14:28.300 It's a male, all male and females have testosterone, but males have more testosterone.

00:14:34.000 Kind of like, where is it made in the body?

00:14:35.640 And like, what are the difference in testosterone levels in men and women?

00:14:39.780 So testosterone, first of all, in adulthood, males have anywhere in puberty, males can have

00:14:47.660 10 to 30 times the level of testosterone as women. 0.97

00:14:50.800 But in Western kind of well-fed populations, it's about 10, males have about 10 to 20 times

00:14:57.780 as much as females, adults, that is.

00:15:00.560 And there's no overlap in testosterone levels in healthy, normal populations of men and women.

00:15:09.440 And so in men, about 95% of testosterone comes from the testes and the rest of it comes from

00:15:19.100 mostly from the adrenal gland and there's some other sources.

00:15:22.400 Testosterone is actually made by many tissues.

00:15:26.060 It's even made in the brain.

00:15:28.240 So it can, most of it comes from the testes and then can enter the brain, but it can also

00:15:34.880 be made de novo in neurons, which is really interesting.

00:15:38.600 And I should just, and so in females, about half is made, you know, these very, very low 1.00

00:15:46.020 levels are made in the ovaries. 0.56

00:15:48.540 And then the rest is made in the adrenal glands and in fat cells.

00:15:53.840 So also, and I should just say, estrogen comes from testosterone.

00:15:59.220 So testosterone is converted into estrogen in males and females, and males also make estrogen.

00:16:07.020 And males who have more body fat are going to have more of the enzyme, which is called 0.94

00:16:12.240 aromatase, that converts testosterone into estrogen.

00:16:16.000 So men who have a high level of adiposity can start to develop some feminine features like 0.79

00:16:22.100 gynecomastia, aka man boobs.

00:16:25.360 And that's because the estrogen levels can really rise due to this high activity of this

00:16:32.220 aromatase enzyme.

00:16:34.000 So in females, estrogen can come from conversion of testosterone in various tissues and from 0.97

00:16:40.860 precursors to testosterone that are produced in the adrenal gland that can then also be

00:16:45.780 converted to testosterone in other tissues.

00:16:49.260 And I should just say that testosterone is an androgen and there are different androgens

00:16:54.220 in our bodies.

00:16:54.940 Testosterone is the main one, but there are other ones like dihydrotestosterone, which is

00:17:00.560 also a product of testosterone conversion.

00:17:03.380 And all the androgens interact with what's the androgen receptor and like a key in a lock

00:17:10.740 basically.

00:17:11.200 And the androgen receptor is present in many, many tissues, again, also in our nervous system

00:17:16.540 and our brain.

00:17:18.120 And what's interesting is that the sex steroids, which are estrogen, progesterone, testosterone,

00:17:27.120 DHT, can all, because they're steroids, because they're fatty molecules, they're lipophilic,

00:17:33.020 they can go into any tissue in any cell.

00:17:35.640 They can just cross the blood-brain barrier, they can get right through cell membranes,

00:17:40.520 inside cells, and they affect gene transcription once they're inside cells.

00:17:45.060 So they're very, very powerful, and they can go everywhere and have these long-term systemic

00:17:50.920 effects on us.

00:17:53.100 I think it's interesting to note that our knowledge of testosterone is relatively new.

00:17:57.840 It wasn't until like the 1920s that scientists are able to actually pin down testosterone, the

00:18:03.080 hormone, but before that, scientists, people, humanity had a hunch that the testicles were 0.86

00:18:10.540 involved in masculizing men.

00:18:13.700 And there's some interesting, I guess we can call them natural experiments that happened

00:18:18.820 throughout human history where we were able to figure out there's something going on with 0.91

00:18:22.160 the testicles that cause men to be men. 0.80

00:18:25.560 And one of them is this really interesting thing that's in Italy, church choirs would 0.99

00:18:30.540 castrate young boys, basically, they're called the castrati.

00:18:34.700 Can you tell us about that?

00:18:35.340 Like, what did we learn about testosterone from that?

00:18:37.980 Yeah, so this is disturbing.

00:18:39.860 I do talk a lot about castration in the book over the ages and in different cultures, and

00:18:45.220 I learned a tremendous amount.

00:18:46.720 And it was all gross because I did get, it's not funny.

00:18:52.260 I did get into the procedure and there's also eunuchs in imperial China and the way that 1.00

00:19:01.340 they were castrated was particularly horrific.

00:19:03.820 But most of the history of castration, so if we just start with the castrati in, say, 18th

00:19:09.980 century Italy, these are, this, what happened was there was a lot of poverty and there were

00:19:17.160 opportunities for kids who were pre-pubertal, who were singers to gain, you know, fame and

00:19:26.600 fortune by singing in church choirs.

00:19:30.640 I mean, some of them could gain great fame and fortune, but even if they didn't have great

00:19:34.700 fame and fortune, they could have some fortune at least and help out their families.

00:19:38.880 And so every year, thousands of young boys were castrated in the hopes of sort of making it

00:19:45.980 big and making it to a church choir.

00:19:48.480 And this is before there was any anesthetic.

00:19:52.020 So a lot of them died and most of them did not make it and had to live lives of a eunuch.

00:20:00.140 So the, what happens is if a kid, a boy is castrated prior to puberty, so most of the people

00:20:09.280 listening are men who have gone through puberty and you know exactly what happens when you

00:20:15.060 go through puberty to your body, to your psychology, to your voice, and sometimes to your hair.

00:20:21.820 You know, some people start going bald fairly soon after puberty, but a eunuch never goes bald.

00:20:27.560 And so what happens is if you remove the testes prior to puberty, and again, yes, this is before

00:20:35.180 anything was known about testosterone, but there were these predictable changes where the period

00:20:40.960 of childhood growth continues for a long time.

00:20:45.460 So it's, and the reason is that in puberty, it is actually rising testosterone that is converted

00:20:52.680 primarily into estrogen, even in boys, that causes the growth of the long bones and that when it

00:20:59.520 plateaus towards the end of puberty, that causes the growth plates in the long bones to seal.

00:21:07.060 And that is why growth, the height spurt stops at the end of puberty.

00:21:11.020 It's actually because of estrogen coming from testosterone, even in boys.

00:21:15.960 But the point is, if you remove the testes, you never have that testosterone increase during

00:21:21.740 puberty.

00:21:22.680 And that growth hormone generated childhood growth.

00:21:27.640 Like I have a 12 year old boy, he's still in that sort of growth hormone period.

00:21:32.460 He's transitioning now to testosterone is going to be taking over.

00:21:35.960 And, but that period is extended.

00:21:39.140 So you get this longer period of childhood growth and the castrated men can end up to be very 0.99

00:21:46.600 tall because they don't have that testosterone peak where growth ends.

00:21:52.160 So they can be very tall and they don't get those secondary sex characteristics that most

00:21:57.040 of your listeners will have developed during puberty.

00:21:59.800 So they retain their head hair.

00:22:02.380 Their voice does not deepen.

00:22:04.640 And that's the, that's the big point is that the voice doesn't deepen.

00:22:08.240 And they retain a sort of high, they retain a soprano singing voice, but they have a much

00:22:15.320 larger body size.

00:22:16.960 They have larger lungs.

00:22:18.480 They have, so they have a powerful soprano voice, more powerful than a female soprano voice

00:22:24.400 and females were not allowed in church choirs.

00:22:26.560 So they needed men basically to fill those parts in the choirs.

00:22:32.600 So that's what castration did for them.

00:22:34.960 But of course, what happens is these men have almost no libido and of course they have no

00:22:42.080 ability to impregnate anybody.

00:22:44.620 So it's, it, that is one of the ways, that's one of the sources of information that castration,

00:22:50.500 even in humans, lowers libido. 0.99

00:22:52.860 So it's something about the testicles is necessary for typical male libido. 0.58

00:22:59.460 And this was also known because there was lots of castration experiments on animals and animals 0.70

00:23:05.820 would be castrated to reduce aggression, to reduce libido for various reasons, to, you know,

00:23:11.560 generate certain kinds of meat, like from a chicken, a castrated chicken has, is, has a

00:23:17.440 large body size and more tender meat.

00:23:19.740 And that's called the capon.

00:23:21.140 And so it's been known for ages that castration of male animals reduces muscle mass, reduces

00:23:28.540 and eliminates libido and aggression in some cases.

00:23:32.740 Yeah. 0.96

00:23:33.340 So there's, was a long, deep knowledge about the testicles and, and the necessity of the

00:23:40.980 testicles for sort of typical male behavior, but testosterone itself was not isolated until

00:23:46.340 1935.

00:23:48.040 And so that took a long time because we've known about this since like the fourth century

00:23:52.560 BC had this information.

00:23:55.120 And yeah, so it, it took until the early 20th century to really identify testosterone and

00:24:01.640 start to try to manufacture it.

00:24:03.120 Okay.

00:24:03.560 So let's talk about like how testosterone makes boys, boys and men, men.

00:24:09.500 And I think oftentimes we think, oh, testosterone only has an effect on a male during puberty.

00:24:14.440 Because that's when you have this huge spike, but you talk about it's that in the influence

00:24:18.220 of testosterone starts in the womb prenatally.

00:24:20.980 So walk us through that process.

00:24:22.120 Like what happens to a fetus when it's exposed to testosterone?

00:24:27.520 Like what's going on there?

00:24:28.900 Yeah.

00:24:29.160 So that's super important that, that prenatal and directly postnatal period.

00:24:34.640 We don't know as much about what testosterone is doing in little boys, little boy babies when

00:24:40.460 it goes up right after birth.

00:24:41.940 But we can talk a little bit about that later, but we know a lot about what it's doing in

00:24:48.100 utero.

00:24:48.500 And I should just say that the way that little humans or conceptuses, which are just that embryo,

00:25:00.920 the very early embryo actually doesn't become male or female because of testosterone.

00:25:06.880 It takes on male and female characteristics because of testosterone, but the determination

00:25:14.360 of male and female is dependent upon the presence of the Y chromosome and the gene on the Y chromosome

00:25:21.800 that is sex determining region of the Y called sex determining region of the Y chromosome or

00:25:27.360 SRY.

00:25:27.940 So if you have the Y chromosome and you have, and it has an intact SRY gene, which almost male, you know,

00:25:35.840 every male will have that. 0.98

00:25:38.060 That is what causes the undifferentiated gonads to differentiate into testes. 1.00

00:25:45.220 So before six weeks, the embryo is not identifiable as male or female.

00:25:52.020 You know, you could look at the chromosomes, but there are no structures or physical differences

00:25:57.080 yet.

00:25:57.480 It's when that gene is expressed that it goes on to cause that tissue, those undifferentiated

00:26:05.060 gonads to differentiate in the testes direction rather than the ovaries direction. 0.99

00:26:11.020 So once that happens, it just takes a couple of weeks for the testes to start pumping out

00:26:15.580 testosterone.

00:26:16.400 So like I was pregnant with a boy and it was just bizarre to know that he was in there with 0.99

00:26:22.260 his little testicles in my body that his little balls are making testosterone that, and that 0.98

00:26:29.560 testosterone is what was necessary for guiding his body and to promote the development of all 0.99

00:26:38.400 the male reproductive structures and physiology. 0.87

00:26:41.100 So his scrotum, his penis, his prostate, his vas deferens, all that stuff is due to the

00:26:49.100 actions of testosterone directly. 0.97

00:26:51.660 And testosterone can do that because, like I said before, it acts on his genes that females 0.90

00:27:00.780 share.

00:27:01.560 Females have the same genes. 0.99

00:27:02.920 It's just that they don't have testosterone to cause the genes to be expressed in a way that

00:27:08.720 grows and maintains the male reproductive structures.

00:27:11.520 So the little fetus has testes that produce a lot of testosterone, and that's what is responsible

00:27:18.780 for the development of the male reproductive structures and male reproductive function that

00:27:24.800 I just described.

00:27:26.000 But at the same time, evolution has done this amazing thing where testosterone at the same

00:27:32.940 time prenatally, as it's working on the body to masculinize it, it goes into the brain because

00:27:40.260 I'm just going to say it knows that this is an animal that needs to reproduce in a way

00:27:47.400 that females don't need to reproduce. 1.00

00:27:49.240 Like this animal has to compete basically for female mating opportunities and is going to be 0.75

00:27:53.820 producing sperm.

00:27:55.060 So this animal is going to, as a little kid, need to do more rough and tumble play, for instance.

00:28:01.320 And females might have to practice nurturing behavior. 1.00

00:28:05.600 So females don't have exposure to testosterone in utero, or they have very typically very, very 0.66

00:28:10.480 low exposure.

00:28:11.960 Males will have high levels of, very high levels of testosterone in utero that masculinize the 0.99

00:28:17.800 body and the brain so that the brain can take advantage of the male body and shape that animal for 0.99

00:28:23.960 male reproductive strategies, you know, which are different than what females need because females 0.97

00:28:28.820 males need to use their bodies to grow their offsprings and feed their offspring, sorry, 1.00

00:28:34.220 offspring.

00:28:34.840 And males don't use their bodies to grow the offspring. 0.97

00:28:39.360 They use their bodies to compete for the right to make, to have a female do the work for them, 1.00

00:28:44.140 basically.

00:28:45.180 And that all starts in utero.

00:28:47.020 And then there's a small rise in testosterone.

00:28:50.400 Sorry, it's a, actually, it's a short-term rise.

00:28:54.100 It's a three-month increase in testosterone shortly after birth.

00:28:59.180 That seems to be very important physically, again, and probably neurologically, but we

00:29:05.880 don't know a lot about it.

00:29:07.700 But there's some hints that it might have to do, might further masculinize behavior and

00:29:12.260 have something to do with penis development and could have something to do with ultimately 0.98

00:29:17.880 penis size. 0.88

00:29:19.200 But there's not a huge amount of work on that yet.

00:29:23.020 Right.

00:29:23.200 So, okay, basically, there's kind of like a mini puberty.

00:29:25.860 That's right.

00:29:26.300 For boys right after they're born.

00:29:28.380 We're going to take a quick break for your word from our sponsors.

00:29:33.460 And now back to the show.

00:29:35.280 So basically, this prenatal exposure to testosterone, is it kind of laying the groundwork, like the

00:29:40.060 wiring for later development in puberty?

00:29:43.700 That's exactly right.

00:29:45.160 So the framework that scientists use to talk about this is called the organizational

00:29:49.980 activational effect or framework.

00:29:53.080 So this is the idea.

00:29:54.440 And this is actually really important because people think all you have to do is shoot up.

00:29:59.740 And this happens, obviously, in like trans men or people who transition their gender. 0.97

00:30:05.660 They will take the hormone. 0.71

00:30:08.660 They'll block their own hormones and take the hormones of the opposite sex. 1.00

00:30:12.200 So, for instance, if a female transitions to live as a male and takes male levels of 0.64

00:30:18.300 testosterone, that testosterone that she's taking as an adult is acting on her brain in 0.98

00:30:26.740 a way that's different from how it would act on a male brain.

00:30:30.400 Because a male brain has been met, the neural structures are permanently masculinized.

00:30:35.340 And these are very subtle.

00:30:36.720 These are very subtle effects.

00:30:38.340 These aren't like huge differences in structures in the brain.

00:30:41.260 These are widespread, small effects on like cell death and synaptic and connections between

00:30:49.500 cells.

00:30:50.360 So these are small effects that seem to have small changes that seem to have important

00:30:55.800 effects in adulthood.

00:30:56.980 So the brain is masculinized in boys prenatally.

00:31:00.780 And then in adulthood, when testosterone goes up in puberty, that testosterone is acting on

00:31:07.020 those previously masculinized neural structures so that if testosterone goes up in adulthood,

00:31:14.440 say in a female whose brain has not been masculinized prenatally, it's going to have a different effect 1.00

00:31:20.180 because it's not acting on previously masculinized structures.

00:31:24.520 And this is hard to study in humans, but it's very clear in non-human animals that you cannot

00:31:31.400 activate typical male sexual and aggressive behavior in female animals whose brains have 0.97

00:31:39.540 not been masculinized prenatally, if that makes sense.

00:31:43.660 Yeah.

00:31:44.540 Does that make sense?

00:31:45.320 That makes sense.

00:31:46.080 That makes sense.

00:31:46.440 And so, okay, this prenatal exposure to testosterone is what gives boys their boyish behavior.

00:31:55.300 So like, what's interesting, so there's-

00:31:56.380 Yeah, yeah, before puberty.

00:31:57.580 Yeah, before puberty.

00:31:58.540 They're like tackling each other.

00:31:59.440 Yeah, so there's a lot of rough and tumble play.

00:32:01.520 I think I've heard boys, this is generally tend to be more object oriented as opposed to

00:32:07.240 person oriented.

00:32:08.940 And what's interesting, like gender differences in toy preferences.

00:32:11.720 You see this even in chimps, they'll give chimps, you know, a toy and the female girl 1.00

00:32:18.760 chimps will like play with maybe like a doll, but like the boys will somehow turn it into

00:32:22.880 like a weapon of some sort.

00:32:25.940 Yeah.

00:32:26.560 I mean, the primate toy studies are less, they're interesting, but I-

00:32:33.960 Not robust.

00:32:34.260 They're less convincing to me than the rough and tumble play.

00:32:38.020 Like we don't even need the toy thing.

00:32:39.620 Okay.

00:32:39.860 Just the rough housing.

00:32:41.280 Yeah, you can look at all these, just look at, take mammals and it's not even confined

00:32:45.340 to mammals, but you could look at chimps, you can look at rats, you can look at a huge

00:32:51.260 variety of animals and you look at the juveniles and there are clear sex differences in play

00:32:58.260 that are parallel in many ways to what we see in humans where the male, the little boys,

00:33:04.760 say in chimps or in rats are tackling each other.

00:33:08.360 They're playing physically.

00:33:09.400 They're, you know, what they're doing is practicing physical competition for status

00:33:14.860 as adults.

00:33:15.520 So they have to practice their reproductive skills, their survival and reproductive skills. 0.66

00:33:19.660 So that rough and tumble play is fun.

00:33:22.460 It has to be fun or else they wouldn't do it and they wouldn't get the practice, but they

00:33:26.280 like that heavy physical play more than females do. 1.00

00:33:30.220 Females are doing other things. 1.00

00:33:31.580 And in humans, we see the exact same patterns and in non-human animals, you can easily manipulate

00:33:39.460 the expression of that behavior by simply suppressing testosterone exposure in boys or increasing

00:33:45.740 prenatal testosterone exposure in females and female juveniles in non-human animals.

00:33:50.900 It looks like it's entirely due to prenatal testosterone exposure.

00:33:56.800 And then in humans, first of all, we have a very large and cross-culturally consistent

00:34:00.960 sex difference where boys like to play physically.

00:34:04.080 You know, I've, again, I have a son, he has friends who are female.

00:34:07.760 I know how they play.

00:34:08.740 I don't see girls getting together in groups and jumping all over each other for hours. 1.00

00:34:14.380 Like boys will tend, you know, on average, not everyone does this and there's overlap

00:34:19.260 in these complex behaviors, but these are broad patterns.

00:34:22.880 And there's a suggestion in humans that it's also apparently, of course, a cultural influences,

00:34:29.180 but that testosterone is the primary driver because we know in girls who have different 1.00

00:34:35.740 conditions, especially congenital adrenal hyperplasia that result in their exposure prenatally to

00:34:42.600 abnormally high levels of testosterone.

00:34:45.220 So it's not as high as boys, but even a slight elevation in girls can have a pronounced masculinizing

00:34:51.060 effect.

00:34:51.660 And so girls that have this condition where their, it happens to be their adrenal gland is 1.00

00:34:57.560 producing relatively high levels of testosterone, that condition is corrected at birth, at least

00:35:03.800 in places with good medical care.

00:35:05.580 And those girls on average end up far more than girls who don't have that condition to 0.99

00:35:12.660 want to engage in rough and tumble play.

00:35:15.440 They want to play with whatever toys the boys are playing with.

00:35:18.820 They're more likely to want to play with boys. 0.99

00:35:21.000 They're more likely to grow up to be lesbians. 1.00

00:35:23.700 They're more likely, even though the rates are very low, to have a male gender identity than

00:35:28.940 females who never had that condition. 1.00

00:35:30.960 And the only difference there is that they had increased exposure to testosterone in

00:35:35.380 utero.

00:35:36.000 There's no difference in the adult hormones.

00:35:38.680 So it's clear that that sex differences in that early exposure to testosterone have a

00:35:44.720 huge amount to do with who we become because this is prior to puberty.

00:35:49.680 So if boys are engaging, you know, more physically active, basically, especially with each other in

00:35:55.800 childhood, that's going to set the stage for later behaviors, you know, almost regardless

00:36:00.740 of what happens in puberty.

00:36:02.620 And this is not all boys.

00:36:04.000 I should say that boys who grow up to be gay are much less likely to engage in rough and

00:36:10.660 tumble play.

00:36:11.840 But those boys, so that's interesting and that's kind of a mystery, but those boys who 0.56

00:36:15.540 grow up to be gay have the same pattern of sexual behavior of boys who grow up to be 0.99

00:36:22.740 heterosexual. 0.76

00:36:23.400 So being exposed to high levels of testosterone in utero seems to always shape male sexual behavior

00:36:31.060 to be masculine, to shape the desire for a higher number of sex partners, ultimately,

00:36:36.060 and a higher libido.

00:36:37.300 Okay.

00:36:37.440 So we've talked about childhood.

00:36:38.700 So prenatal testosterone sort of lays the groundwork.

00:36:41.240 Throughout childhood, T levels between males and females are pretty much the same.

00:36:45.360 Yeah.

00:36:45.560 And then puberty happens and there's this spike.

00:36:47.580 And I think we all know what happens during puberty, like the secondary sex characteristics show

00:36:51.280 up, you get taller, more muscle mass for men, body hair, facial hair, deeper voice.

00:36:57.180 What's going on though on the brain?

00:36:58.800 Like how is that testosterone surge influencing the mind and behavior?

00:37:03.240 I've talked to a lot at this point, just in talking about the book, a lot of men and

00:37:08.740 trans men, which is interesting, you know, people who lived as women and then took high

00:37:12.060 levels of testosterone about what it feels like.

00:37:15.420 Most men say that they were preoccupied with sex, preoccupied with their position in the

00:37:23.560 status hierarchy and social relationships among boys and then young men.

00:37:28.520 So again, you know, I have this 12 year old and that's what he talks about a lot.

00:37:32.040 He's not the sex part, but the, who is popular, what they do, how they behave.

00:37:37.360 And this is all fascinating because it seems all of them are really, really attuned to status

00:37:43.480 hierarchies, you know, and there's a great evolutionary reason for that.

00:37:46.720 And testosterone is promoting that.

00:37:48.940 Girls have their own hierarchies too. 1.00

00:37:51.220 That's also extremely important, but the way they navigate competition within those hierarchies 0.55

00:37:56.780 is totally different.

00:37:58.340 Girls don't use this like very direct form of aggression and physical aggression. 1.00

00:38:02.560 They tend to use gossip and passive aggression and backstabbing.

00:38:06.300 I hate to say, and now social media, which I think that's a horrible way to harm people's

00:38:11.820 reputations.

00:38:12.700 Boys are more likely to go up into somebody's face and call them an a-hole or something.

00:38:17.240 And so there are these, and they're more likely to get into obviously physical, aggressive,

00:38:22.320 physically aggressive interactions.

00:38:23.560 And of course that depends on culture, you know, around the world and just within say our

00:38:28.420 United States, like there's obviously different norms around beating other guys up.

00:38:34.980 Right.

00:38:35.380 Different cultures.

00:38:37.600 So yeah, I think that's what's going on psychologically is sex and status competition.

00:38:42.780 And I think the point to make is that there is a cultural, like, so we have this biological

00:38:46.020 thing going on, but like culture can kind of direct it, right?

00:38:49.780 So in the West, it's like, well, how do you get status?

00:38:52.940 It's like, well, you go, maybe you play football or you run for student council or it's like if

00:38:57.180 you're a teenage boy.

00:38:58.280 That's right.

00:38:58.640 You can gain status that way.

00:38:59.540 In another culture, it might be something different, but there'll be a drive for status 0.79

00:39:04.300 somehow because the idea is like, if you get status, the chicks will like you. 0.99

00:39:09.320 Yeah.

00:39:09.920 I mean, but you don't, you might not even think of it that way at the time.

00:39:13.240 You just seem driven to gain status over other boys, you know, or young men.

00:39:19.460 And yeah, it seems like a benefit is that the girls start to pay attention to you.

00:39:23.580 So culture, people sort of miss this point about how incredibly important culture is

00:39:30.740 and nobody should resist the facts of biology about, you know, and the role in all of these

00:39:38.240 types of behaviors.

00:39:39.560 They shouldn't resist that because they think that culture is important or culture is more

00:39:44.640 important.

00:39:45.220 It's incredibly important.

00:39:46.700 But what's interesting is how it interacts with our biology in these fascinating ways that

00:39:53.020 have an important evolutionary explanation.

00:39:56.500 Well, I think you, you made some, some guy, I forgot who it was.

00:39:58.900 I think it's the guy that wrote the trouble with testosterone.

00:40:01.180 I forgot his name.

00:40:01.580 Robert Sapolsky.

00:40:02.460 Yeah.

00:40:02.700 He said like, if you talk about the influence of culture and biology, kind of the interplay

00:40:06.980 they have, it's like, if you gave testosterone to a bunch of monks, they would start competing.

00:40:13.460 Like they wouldn't start beating each other up.

00:40:14.900 They would start trying to out-compete each other who can meditate the most or who can do

00:40:18.400 niceness or something.

00:40:19.600 Yeah.

00:40:19.700 But if you gave like testosterone to a prison gang-

00:40:23.420 That's right.

00:40:24.100 You'd probably see just a bunch of, you know, shanks and things like that. 1.00

00:40:27.220 Yeah.

00:40:27.520 That's what's fascinating is that it seems to promote whatever is necessary for a man or

00:40:36.260 an animal, you know, in a given environment to gain status or to, you know, avoid, just

00:40:43.240 to avoid being, to avoid losing status, say.

00:40:46.720 So it sort of increases your attention to those signals of status is how it seems to

00:40:53.300 work.

00:40:53.740 Your vigilance and your attention and your striving for status in whatever way is necessary.

00:40:59.580 And in our deep history and still in many parts of the world, that was physical aggression.

00:41:04.260 So that's why males are larger than females and still are, you know, so there's still

00:41:09.900 those cues and women are still attracted to big, you know, tall, say, muscular, assertive

00:41:17.960 men, even if there isn't any actual reproductive benefit.

00:41:23.140 It's that's how women are wired. 1.00

00:41:24.380 So males are also still wired to, yeah, really care about status and be responsive to those

00:41:31.380 cues in a way that women, you know, are responsive to different kinds of cues. 1.00

00:41:35.380 And status just is not quite as important for female reproduction, of course, as it is

00:41:40.360 for men.

00:41:40.840 It still matters because females want to compete for the high status males and there aren't 1.00

00:41:46.060 that many of them.

00:41:47.540 Well, let's continue on this, this, this status strain here.

00:41:50.140 So I think it's interesting, you talk about studies that testosterone can, I mean, okay,

00:41:56.160 influences this drive for status chronically, systemically.

00:41:59.220 So it just kind of wires you for that.

00:42:00.720 But there's these like acute things going on.

00:42:03.120 If, if a male experiences an increase in status or a decrease in status, there can be these

00:42:10.020 sudden drops of testosterone or increases in testosterone, testosterone.

00:42:15.080 Like what, what causes such a rapid change?

00:42:17.220 Because I mean, the production of testosterone takes a while.

00:42:19.080 It has like the pituitary gland, it's a signal.

00:42:20.800 Very good.

00:42:21.440 So like what, what causes that super fast?

00:42:23.880 Like, I mean, it's even like, it's so weird.

00:42:25.680 Like a guy can watch his favorite sports team lose and like his T levels will drop immediately.

00:42:30.700 So like what's going on there?

00:42:32.580 Yeah.

00:42:32.960 So I don't want to overstate the prevalence of this phenomenon.

00:42:38.440 And however, it does exist in it, in humans and in non-human animals.

00:42:43.240 And I think it'll be helpful just to say what happens in non-human animals.

00:42:46.520 So the Syrian hamster has been studied heavily regarding these testosterone changes, which

00:42:53.160 I think are very important in humans.

00:42:55.620 And again, it's not so much how much testosterone you have as a guy in general, as long as it's

00:43:01.280 within the normal range, your sort of baseline level seems not to be super predictive of much.

00:43:07.400 What does to me seem to be important is prenatal testosterone and these changes that you're

00:43:12.180 talking about in social, that are a product of social interactions.

00:43:16.860 And this to me is, is absolutely fascinating.

00:43:19.820 So in Syrian hamsters, if a Syrian hamster has a fight with another male for territory,

00:43:27.440 so territory is the equivalent of any kind of resource in humans, because you need territory

00:43:31.420 to get females because females will, will feed on the territory that a male can guard basically. 0.61

00:43:37.220 So high status males will have larger territories in the wild anyway.

00:43:41.660 And the outcome of, if you think about it from an evolutionary point of view, or even

00:43:45.780 think about it from today.

00:43:47.200 So if you're fighting physically with another guy, if you lose, you need to know on some level 0.99

00:43:54.060 that you're a loser. 0.86

00:43:55.280 Like you can't go, if you're losing consistently against other males in physical competitions, 0.98

00:44:01.580 you need to stop, you need to run away.

00:44:04.440 Basically, if somebody's in your face, you need to run away.

00:44:07.560 You shouldn't be challenging them because you want to survive to try to win some other

00:44:11.840 competition in the future so that you can mate, right?

00:44:14.300 So how do animals make those decisions about how do they know, well, I need to, you know,

00:44:21.580 fight or I need to flee, right?

00:44:23.600 Those are decisions that animals have to make.

00:44:25.400 So when you're, when someone's threatening you, it may trigger in you the feeling that

00:44:31.300 they're threatening you physically, even if it's just a chess game or a tennis match, definitely

00:44:36.660 in a football game, or just some guy is in your face.

00:44:40.260 There's all kinds of situations where two males are competing for status in humans in some

00:44:46.160 way, right?

00:44:46.740 So in the, in the hamsters, if a male loses a physical fight and he submits, right, he ends

00:44:55.020 up by going on his back and getting on his back and submitting, his testosterone will tank.

00:45:00.800 So first of all, when they're facing off, they're, both of them have an increase in testosterone.

00:45:05.260 The loser will have a pronounced decrease in testosterone.

00:45:09.300 The winner will maintain high testosterone or it will get higher.

00:45:12.940 And if you, and then the loser will fail to defend itself or defend its territory against

00:45:20.720 a future threat because he's lost, he's that, that reduction in testosterone is somehow telling

00:45:27.000 him he should be scared and run away.

00:45:29.800 So if you block that, that reduction in testosterone after he loses, he'll continue to defend his

00:45:38.000 territory and challenge other males. 1.00

00:45:39.660 And then he'll get his ass kicked and he could die, right? 1.00

00:45:42.260 So it seems like the testosterone drop is adaptive for losers. 1.00

00:45:47.280 A testosterone rise is adaptive for winners because it's a way of signaling, shaping the

00:45:53.740 animal for future encounters.

00:45:55.860 So if you're a winner, you know, in the face of threat that you're a winner, you act like

00:46:00.400 a winner.

00:46:01.020 You don't back down.

00:46:02.120 You take on the challenge.

00:46:03.540 If you have lost, you are fearful and anxious and you retreat from confrontation.

00:46:08.980 So we have all varieties in humans of those responses to competition, but it seems like testosterone

00:46:16.640 changes in the moment, in the face of competition are playing a role neurologically to set people

00:46:23.960 up for reaction to future competitions and may help to account for different, uh, even in

00:46:31.760 ways that people engage in competition in general and just, uh, feeling like they are fearful

00:46:39.020 or feeling like confident in the face of, uh, competition.

00:46:43.040 So yes, there's all kinds of examples in the human literature where either from sports or

00:46:50.580 again, from competitions that are not physical even.

00:46:54.460 And then there's all these competitions that we don't measure, which are just males getting

00:46:58.400 each other in each other's faces in some way, having subtle competitions where there

00:47:03.520 are these testosterone changes.

00:47:05.480 It's tough to pin down experimentally, like exactly when they happen and who they happen

00:47:10.040 in and exactly what the function is.

00:47:12.600 But from the literature on non-human animals, it seems clear that we do know that when testosterone

00:47:18.720 rises in these social situations, it can increase dopamine, which is a hormone that is rewarding

00:47:27.900 and, and promotes the same behavior in the future because it, so it increases motivation

00:47:33.920 for the same behavior in the future because it felt good last time.

00:47:37.300 And cortisol is a hormone that is associated with stress and anxiety, and that can be paired

00:47:42.780 with the testosterone drop and that can possibly motivate the animal more towards a retreat

00:47:49.180 strategy in the future.

00:47:51.160 So there's like a Matthew effect going on, right?

00:47:53.420 He who has will be given more, he who doesn't have will be taken away from.

00:47:58.520 So yes, I think that's right, but it's adaptive for all basically based on, but it's a way to,

00:48:04.300 you know, if you're in a stressful situation, it's possibly a way to, um, condition males to,

00:48:12.780 about how to respond very quickly so they don't have to stop and think about it.

00:48:16.940 And I should just say, you raise a really interesting question.

00:48:20.640 How does testosterone change in these situations?

00:48:23.340 Because like you said, the signal to produce testosterone in the testes comes from the brain.

00:48:29.780 It comes from the hypothalamus and pituitary in the form of luteinizing hormone.

00:48:34.380 And it takes an hour for that hormone to get from the brain to the testicles and to result 0.88

00:48:40.360 in a, in, in a pulse of testosterone, essentially, then that testosterone have to go through the

00:48:45.480 blood and alter gene transcription, which, you know, theoretically should not have immediate

00:48:50.180 effects on behavior.

00:48:51.800 So the answer is, we don't know how social interactions can cause these testosterone rises.

00:49:00.040 It may be that it's not coming from the testes, or it may be that it's not coming from LH,

00:49:04.760 it may be that there's an increase in adrenaline and that somehow adrenaline acts on the testes

00:49:11.980 to release testosterone that's kind of hanging out there, but we don't know.

00:49:17.400 And this is something that I've been obsessed with a long time.

00:49:20.380 What is the mechanism here?

00:49:22.240 Okay.

00:49:22.380 So testosterone makes a boy or, you know, teenage boys, young adults, young adult males,

00:49:27.860 preoccupied with sex, preoccupied with status.

00:49:29.820 Well, I wouldn't say makes, but yes, heavily influenced.

00:49:32.440 Heavily influenced.

00:49:33.100 Yeah, right.

00:49:34.120 But, and then also we've talked about this a little bit, aggression, like it makes,

00:49:37.780 causes or influences males to be more aggressive.

00:49:41.420 And what's the, the advantage of that?

00:49:43.200 I mean, what's the advantage of being aggressive?

00:49:44.700 Is that just helps you get access to mates and resources? 0.53

00:49:47.620 Is that the, the idea?

00:49:49.820 So there's no, there's actually not a big sex difference in aggression.

00:49:54.680 Okay.

00:49:55.240 Just broadly.

00:49:56.280 It's really physical aggression.

00:49:58.260 Okay.

00:49:58.620 Physical aggression.

00:49:59.220 Using, so, and what's interesting is if you think about the strategies over human evolutionary

00:50:05.320 history that males and females would use to maximize their reproduction.

00:50:09.500 And, and that's what natural and sexual selection acts on is, you know, the traits that animals

00:50:16.940 possess that allow them to maximize reproduction.

00:50:19.200 So for females, taking physical risks is a bad idea because you need your physical integrity. 1.00

00:50:25.560 You need energy.

00:50:26.880 You need safety.

00:50:27.660 You need a long, a long, healthy life.

00:50:31.100 That's what, because you don't have to worry about fighting for mates, right?

00:50:33.940 You have to worry about having the energy and health that you need to bear and feed your

00:50:40.340 children and you have to care for them.

00:50:41.740 So it doesn't pay off for females to take physical risks and they don't have that need to compete 1.00

00:50:49.840 physically for mates, although they compete for mates, but in ways that don't put their

00:50:54.420 physical selves at risk typically, right?

00:50:57.300 So males are relative to females over evolutionary history have benefited from physical aggression

00:51:05.460 because they, that's what their bodies are in a sense built to do relative to females. 1.00

00:51:10.700 That's where they're putting their reproductive energy budget. 1.00

00:51:13.680 That's why they have bigger bodies and more muscle. 0.50

00:51:16.400 That's the only reason relative to females. 1.00

00:51:19.300 So that muscle, that's a history of using their bodies to compete physically for mates. 1.00

00:51:24.900 So we retain that in a modern environment that, and that's a, you know, again, that's attractive

00:51:30.360 to females. 0.85

00:51:31.320 It's not the case that they have to compete physically anymore.

00:51:35.620 So in different cultures, women are going to prefer men who have high status, whether it's

00:51:41.820 gained physically or not.

00:51:43.680 Like I'm married to a philosophy professor and he's definitely never gotten into a fight,

00:51:49.720 but he's super attractive to me, partly because, you know, partly because of his status, but

00:51:55.820 it's not, you know, he got that with his brain, not with his body, but it depends on the environment

00:52:01.780 you're in and what pays off.

00:52:03.340 So we have this evolutionary history of physical aggression paying off, but it still plays

00:52:08.880 out in the extremes.

00:52:11.080 Yeah.

00:52:11.440 I mean, you can see the propensity for physical aggression in males, just like crime reports.

00:52:15.840 If you look at murders, physical assault, sexual assault, it's pretty much all dudes.

00:52:21.220 You know, there's, there's women there every now and then, but it's mostly dudes. 0.99

00:52:23.620 But then if you look at crimes like fraud, shoplifting, et cetera, there's still more men, but

00:52:29.580 you know, women, that's more of where they kind of do their crime. 1.00

00:52:32.640 If they're going to commit crimes.

00:52:33.380 Yeah.

00:52:33.500 That's where the sex difference is reduced.

00:52:35.180 So women are going to commit crimes, but they're not going to, they're just much less likely 1.00

00:52:39.360 to put themselves physically at risk to commit those crimes.

00:52:44.500 Males are much more likely to put themselves physically at risk to commit crimes and to do

00:52:49.460 everything else.

00:52:50.180 Like to show off to, you know, thrill seeking men are just far more likely to do that physically.

00:52:56.960 Okay.

00:52:57.440 So we've talked about testosterone's effect on behavior in males.

00:53:02.020 Something that's been getting a lot of press lately is the role of testosterone in athletic

00:53:06.120 performance.

00:53:07.060 What do we know what's going on there?

00:53:09.760 So there's a lot of controversy and confusion around this area, but I'll just say that the

00:53:18.920 science is clear.

00:53:20.040 It's not confusing.

00:53:21.440 And people who try to make it seem confusing from my point of view, have a political or

00:53:28.160 ideological agenda.

00:53:31.400 It's totally clear that in the almost all sports, there are some exceptions, males, men.

00:53:40.540 So if you're looking at the elite level, if you're looking at, you know, comparing highly trained

00:53:44.520 people, you know, who are all taking care of themselves, all healthy, eating well, sleeping,

00:53:49.360 training, you know, et cetera, men blow women out of the water. 1.00

00:53:53.440 It's, it's no, there is no competition.

00:53:56.080 There are in many sports, even at the Olympic level, there will be thousands of men who will

00:54:05.000 be better than the number one female. 1.00

00:54:07.280 And that's almost the case across the board.

00:54:09.440 In some endurance sports, there are some exceptions to that.

00:54:13.180 The reason is testosterone.

00:54:16.480 Like it is, again, this is abundantly clear that this is an effect, a consequence of males

00:54:23.760 going through puberty.

00:54:25.620 Like for all the reasons that I, you know, all the things we've been talking about physically,

00:54:30.840 nevermind what might be happening psychologically, which, which is a question, but the physical

00:54:36.660 advantages are immense in terms of the, what happens that is irreversible, first of all,

00:54:43.620 in puberty.

00:54:44.140 So there is some aspects of pupital changes that are reversible and, but there's others

00:54:49.080 that are not.

00:54:49.940 So the ones that are permanent are obviously the bone growth.

00:54:53.440 So the height, bone density, to some extent is irreversible.

00:54:57.740 Testosterone causes increase in bone density.

00:55:00.920 And that happens because of the increased muscle during puberty that exerts forces on the

00:55:06.740 developing bones that causes them to increase mineralization and density.

00:55:12.200 So you have stronger, taller bones.

00:55:14.680 So you have larger bodies and on those larger bodies have much more muscle and testosterone

00:55:22.960 causes stem cells during puberty to differentiate into muscle, preferentially over fat.

00:55:30.600 So those don't reverse so that in adulthood, if you suppress, if you're a man and a male and

00:55:38.720 you suppress your testosterone, you will not lose all of that muscle advantage you would

00:55:44.380 have over a typical female. 0.98

00:55:46.580 So there's height, there's bone density, there's larger hearts and lungs, there's increased hemoglobin.

00:55:55.780 So males have significantly more hemoglobin.

00:55:58.020 That's a direct effect of testosterone and hemoglobin carries oxygen around the blood.

00:56:04.540 So you'll have more oxygen fueling the greater amount of muscle mass.

00:56:10.700 You have massively higher upper body strength.

00:56:14.300 Males, again, the upper body strength just blows away the upper body strength of females. 1.00

00:56:21.100 You have greater throwing capacity.

00:56:23.440 You have greater grip capacity.

00:56:26.220 I mean, I could go on and on and you have more power.

00:56:30.900 So sports that emphasize power, like weightlifting, like Laurel Hubbard, for instance, is a trans

00:56:39.220 woman who competed in weightlifting in the Olympics recently.

00:56:44.620 And there was a lot of controversy and questions about whether she, because she was a person who

00:56:51.520 was male, who transitioned to living as a woman and had stopped her testosterone and taken estrogen.

00:57:01.120 And the question was, would she have an advantage in weightlifting over natal women? 1.00

00:57:08.480 And the answer is yes, because she went through male puberty.

00:57:11.840 She's going to have a huge advantage because all of her muscle mass that she gained as a result of male 1.00

00:57:17.580 puberty doesn't disappear even when testosterone is stopped for something like even five years.

00:57:23.240 So there's enormous advantages to going through male puberty.

00:57:27.600 And those do not disappear when testosterone is suppressed in trans women.

00:57:34.600 And that's just indisputable.

00:57:36.540 There's just no, it's not that women, some people are saying women aren't trying hard enough. 0.99

00:57:41.220 And that's why they're losing.

00:57:44.240 That's just a joke.

00:57:45.380 That is a joke.

00:57:46.040 So, I mean, when people finish this book, like, what do you hope they walk away thinking?

00:57:50.580 Yeah, I mean, there's a couple of things.

00:57:52.440 Of course, I'm incredibly interested in testosterone and the power of testosterone and how it shapes who

00:57:59.080 we are.

00:57:59.600 But I think one of my overarching values in life is that science and knowledge is, it's crucial for us

00:58:09.400 to have clear views about reality and to not fear the truth and to do whatever we can to find and

00:58:17.800 communicate the truth.

00:58:18.700 That's what I see my job as a science educator.

00:58:22.100 And that when you learn how things work, you have more power to make the world a better, safer, more

00:58:29.540 equitable place.

00:58:31.280 And so that is one thing I want people to come away with.

00:58:34.080 I want them to see that it's possible to be clear and honest and open, but also sensitive

00:58:39.540 and compassionate.

00:58:40.720 And then the other point is, of course, about the hormone.

00:58:43.980 There's just so much evidence that this one molecule shapes our society in these really

00:58:50.780 profound ways.

00:58:52.040 And that the more we understand about how it works, the more we can capitalize on the positive

00:58:57.240 aspects of being a man, which we didn't even talk about.

00:59:00.380 We didn't talk about toxic masculinity, which I really don't like at all.

00:59:04.820 I don't like that term.

00:59:05.900 I don't like the concept either.

00:59:07.360 I don't want him to be exposed to that idea.

00:59:09.420 He already is.

00:59:10.480 And I don't like that at all.

00:59:11.920 I want him to be, I'm tearing up here.

00:59:15.020 I want him to be, you know, proud.

00:59:17.300 Sorry.

00:59:17.960 No, it's fine.

00:59:20.680 Sorry.

00:59:21.260 I feel so deeply about this.

00:59:23.960 Nobody should be ashamed to be a man, to be masculine.

00:59:27.440 And we didn't talk about heroism.

00:59:29.200 And if you look at the news and who's risking their lives to save the lives of others, it's

00:59:34.340 men, typically.

00:59:35.460 You know, there are really brave women who are doing that too.

00:59:38.640 But over, I don't know why I'm getting so upset.

00:59:40.640 I'm sorry.

00:59:41.180 No, you're fine.

00:59:44.460 It's men.

00:59:45.180 And I think there are a lot of struggles that we need to acknowledge that men are facing.

00:59:51.040 And I wish we could just be open.

00:59:53.140 And some of those struggles are around puberty and adolescence.

00:59:55.900 And I wish that more people felt they could talk about their struggles and have support.

01:00:01.460 And that this ultimately is the way to making the world a better place.

01:00:05.040 And there's so much positivity around masculinity.

01:00:08.820 And that should be celebrated and encouraged.

01:00:11.360 And this whole narrative about toxic masculinity that seems to be increasing, I wish would end.

01:00:17.800 I wish it would end.

01:00:18.440 No, I think that's, I think that's, I like how we ended on that.

01:00:21.900 Because I think, I think it's true.

01:00:23.500 I'm tired of the toxic masculinity discourse.

01:00:25.540 I don't think it's helpful.

01:00:26.780 I don't even, I don't even know what it means anymore because it gets bandied around so much.

01:00:30.780 But then we also forget about all the great things men do.

01:00:34.400 And I think that's, I think men need to hear that as well.

01:00:36.760 Because I think you're just kind of scolded all the time in the popular culture and it can get you down.

01:00:42.080 Yeah, and I'm, you know, you're, I assume working hard and being a great dad.

01:00:47.700 I mean, to me, having that involvement in the family and having that kind of support and men bring something to the family that women just don't. 0.99

01:00:56.460 And I watch this in my own family, the way that I am with my son and the way my husband is with my son is very different.

01:01:02.740 And he needs, he needs that.

01:01:04.600 I'm not saying that people won't, that every family has to have a male and a female or a mom and a dad.

01:01:10.920 Because of course they don't.

01:01:12.300 But there is something that is so important that dads are bringing to the family.

01:01:18.180 And again, and also I have to, people aren't going to like this, but to the world, there is a different way of being in the world that I'll just say quickly.

01:01:27.020 And that I asked my students at the end of class, I usually ask them, what would the world be like without men or something like that?

01:01:35.520 And just a couple of years ago, a student said, I don't think we'd have tall buildings.

01:01:39.700 Or I think I said, what would happen if we castrated men? 0.99

01:01:41.800 Or some other student said, you know, we should castrate all men or something ridiculous. 0.98

01:01:45.240 And this other student spoke up, which was great. 0.96

01:01:47.720 I don't think you'd say that today.

01:01:49.180 He said, I don't think we'd have tall buildings.

01:01:50.940 I don't think we'd have the kind of innovations that we have.

01:01:54.060 And that's controversial, of course, but there is something to it.

01:01:57.340 That competitiveness, that drive for status sometimes can be destructive, but can also be incredible motivation for innovation.

01:02:06.860 And that's something that remains to be explored.

01:02:09.280 It's sort of too politically incorrect, probably to study it seriously, but I wish we could.

01:02:14.800 Well, Carol, this has been a great conversation.

01:02:16.200 Where can people go to learn more about the book and your work?

01:02:18.660 Okay, so I have a website, carolhooven.com.

01:02:22.500 I'm on Twitter at Hoovlet and H-O-O-V-L-E-T.

01:02:28.120 And my book is on Amazon and wherever you like to get your books.

01:02:33.000 And if you do get it and like it, I never ask people to do this.

01:02:36.340 I keep forgetting.

01:02:37.140 Just if you could review it on Amazon, that really helps.

01:02:40.140 And yeah, so I'd like to get more reviews.

01:02:43.080 Fantastic.

01:02:43.380 Well, Carol Hooven, thanks for your time.

01:02:44.360 It's been a pleasure.

01:02:45.400 Thank you so much, Brett.

01:02:46.740 I've enjoyed the conversation.

01:02:48.960 My guest name is Carol Hooven.

01:02:50.260 She's the author of the book, Tea, the Story of Testosterone.

01:02:53.340 It's available at Amazon.com and bookstores everywhere.

01:02:55.500 You can find out more information about her work at our website, carolhooven.com.

01:02:58.960 Also check out our show notes at aom.is slash tea, where you can find links to resources,

01:03:03.160 where you can delve deeper into this topic.

01:03:11.380 Well, that wraps up another edition of the AOM podcast.

01:03:14.080 Make sure to check out our website at artofmanless.com, where you find our podcast archives,

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The Art of Manliness - December 06, 2021

How Testosterone Makes Men, Men

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