Ep 194: Sex Hormones and Your Teen’s Brain

Andy:
You certainly have done a lot of work in this area and you've written numerous books on all kinds of brain-related subjects. Specifically, I just read both of your books on the male brain and on the female brain, and there is so much helpful, fascinating information in here. It really got me wondering what inspired you to get into this. You talk in the book about having a moment of realizing that so much research was using male animals and male brains as the default, and that there was just really a lack of looking at the female brain at all.

Louann:
Yeah. What you need to know is that the research into the brain for many, many years, most years up until about recently had been done on the male brain, the male brain in animals and the human male brains and male bodies in general. A lot of research, medical research and all kinds of research has been done mostly on males, which has really left the female brain or female body out, and it's not entirely a nefarious reason that they've done that.

Louann:
I remember raising my hand in medical school when I was about in my second year of medical school and asking the professor, because he just explained this really interesting study on something and said, "Well, the males, this, blah, blah, blah, blah, blah," but he didn't mention the females. So I said, "What about the females?" And he says, "Oh, we don't study the females because their menstrual cycles will just mess up the data." I thought, "Whoa!" But no, but it's like I look back at myself and I'm embarrassed, because I thought to myself, "Oh no, no, no." As a scientist, I thought, "Oh, you wouldn't want to mess up your data. Of course not."

Andy:
Oh, yeah.

Louann:
I totally bought into it too, at that time. It didn't occur to me until later in my career that, whoa, something's wrong with this picture. Of course, there's another reason that human females are not studied so much in lots of times of medical research is because the chance of if the female may be pregnant, then you may injure the fetus, so it's not just messing this data up with the menstrual cycle. It's also that the female be pregnant. And I remember asking a male scientist once, I said, "Well, why don't you just ask them if they're pregnant?"

Andy:
Oh, that is a good question.

Louann:
Or why don't you just do the pregnancy test before they come in? They had never even thought of that. I thought, "Oh my God." Anyway...

Andy:
Wow, you're right. We could do that. There's also, interesting, this assumption woven into that line of thinking that they're interchangeable. "Ah, yeah. The female brain is pretty much just the same as the male brain, except it's a little more harder to study because there's all these fluctuations going on every month, so we could just kind of eliminate them."

Louann:
Exactly. Anyway, I got very interested in my undergraduate years in hormones and behavior. I was at UC Berkeley in my undergraduate years, and it was at the time when all the studies that they were doing were discovering the actual effects. And remember, the purpose of a hormone is to cause a behavior. For example, your hunger hormones make you eat and your sex hormones make you want to have sex, so the purpose of a hormone is to cause a behavior.

Andy:
Okay.

Louann:
And of course, I was in my early twenties and they were studying the testosterone hormone and how it caused sexual interest and sexual behavior in both males and females, and so I was very interested in that, of course, and I got just obsessed with how hormones in our body change our behavior and make us want to have a behavior. So that's where I got very, very interested in it, until I got in medical school. Then I got really interested when I did my psychiatry rotation and found that the depression ratio in male and female to male is about two to one, females being much higher, and with anxiety disorders being four to one, very much higher in females to male. But in childhood, it's about one to one until you enter puberty, until age about 12 to 14. And I thought to myself, well, what happens in age 12 to 14 in girls?

Andy:
Right. What's going on?

Louann:
They start their periods. It's the menstrual cycle happens, and when the menstrual cycle starts in puberty, that's when that anxiety, depression level goes up and doubles in females to males. So that's when I got really obsessed with it and I started the Women's Mood and Hormone Clinic, and then I also started the Teen Girls' Mood and Hormone Clinic at UCSF when I became a professor there. So that has been my life's work, is looking at the hormone effects in the brain and with a particular interest, of course, in the teen brain and in the female brain.

Andy:
I thought that was really fascinating as well, the statistics that you mentioned on depression and anxiety, and I'm interested to hear a little bit more about that. There's a number of other things that you point out in your books about some of the differences in some of the sizes of some of the areas of the brain, which I thought were really interesting, in terms of things like language areas of the brain are larger in females.

Louann:
Especially three or four days before ovulation, the females become much more talkative, and the circuits in the female brain for running our talkativeness and even our tone of voice. The studies have shown that our tone of voice gets a little bit higher-pitched and we sway our hips a bit more, and we don't even realize we're doing some of this. Also, we dress a little bit sexier or maybe put on a little bit more something in hair and makeup. The studies that have been shown that women do that three to four days before ovulation happens.

Louann:
I say that's how Mother Nature made it, so that we will attract the best sperm. That's the whole purpose. The purpose of the female is to attract the best sperm and procreate, keep the species going. And for you guys, the male's purpose is with all that testosterone that happens. Remember, it goes up about times 250 between age nine and 15 in boys. It just looks like if you looked at... Remember the COVID curve? Sometimes they just go straight up to the sky.

Andy:
Yeah, yeah, yeah, yeah.

Louann:
That skyrocketing, that's what's happening in the testosterone, in the male brain at that time. His job becomes, and that hormone is driving him to search out fertile females and impregnate them and get on with procreating the species. That's the male's job on the planet according to Mother Nature. Of course, I say that tongue-in-cheek, because obviously, we had to learn to behave in a civilized manner. But yeah, it goes straight up. It's just amazing.

Andy:
I could not believe this chart that you have in your book showing the testosterone levels in males over the lifespan. It goes straight up. It's like a cliff and then it really peaks around a little after age 15, and so that's all going on. I started to learn about from these books is how those hormones are then causing changes in the brain.

Louann:
They do. They basically start to run the circuits that are. I think that happens, and I talk about that a little bit in the book. Remember, both of the books in chapter two is the teen brain, so the teen girl brain is in The Female Brain and the teen boy brain is chapter two in The Male Brain. If any parents or anybody wants to just check out what's going on, they can just turn to chapter two in either of those books and see what's going on, and see the graph that you were talking about going skyrocketing with the testosterone.

Andy:
Although I wouldn't skip the stuff about childhood, because it really, I feel like, lays the groundwork for what you learn about in the teen chapters. I found it really helpful to start seeing the big picture, and when you can see, "Oh wow. So that even starts from six months old," and start seeing these patterns play out over the lifespan then. Yeah, it just puts things into context, I guess.

Louann:
Absolutely. Wait, let's roll it back to the very, very beginning. Okay, let's talk about when sperm meets egg. Right? Okay. If the sperm is carrying an X chromosome into the egg, it'll be XX. That's female. If it's carrying a Y chromosome and it enters the egg, it'll become XY. That's male. So at six weeks of fetal life, the tiny testicles in the male fetus start pumping out a huge amount of testosterone, like male levels of high testosterone. It marinates the entire brain and body, changing the brain and body into male. In the female fetus, from the moment of conception on, her brain and body develop unperturbed by testosterone.

Louann:
And so at birth, both of them pop out with basically the basic imprinting and circuitry and body type of either the male or female. The testosterone actually kills off the female uterus, kills off the vagina and ovaries, and that makes the testicles develop. The default biology is the female, so unless there's testosterone, it will develop as female.

Andy:

And then you write about some studies, I guess, that have been conducted with this condition where female babies do have a high level of testosterone.

Louann:
Right. One of the ways we understand how powerful these hormones are at shaping the brain and body during fetal life is from some disorders. One of the disorders is called adrenal congenital syndrome, which is when the adrenals end up making a lot of testosterone in the female fetus, so the female fetus gets a lot of testosterone going on. She is usually born with a larger clitoris, and sometimes they mistake it as being male. Not anymore, because they do the genetics, but that would be male and her brain has been masculinized by that testosterone from her adrenal. That's called congenital adrenal syndrome. And the other one in the males is a male genetic that causes, the receptors don't respond to the testosterone at all, so it's as if he's developing without testosterone. So his genetics may be XY, but his whole body and brain will develop along the female line.

Andy:
Interesting.

Louann:
It's called androgen insufficient. There's a few of them that are genetic. We've learned a lot from those in terms of what the typical development is and what it is if it's skewed in the direction of more or less testosterone in the male or female. Isn't that cool? I find that so interesting, the results in that, and that's a whole other area of medicine that I find. It's called pediatric endocrinology. It's quite interesting. The thing to remember is that a lot of this stuff is laid down by the time we're born, and then the things that parents do or don't do to kids, the behavioral thing. We'd say, "Boys don't cry." We really try to toughen up the boys and all cultures do that.

Andy:
Okay.

Louann:
Not all cultures, but most cultures will do that to boys. You probably remember that yourself. It was like you're expected to man up over things. So there's a lot of pressure, social pressure to behave in a certain way, and that affects the outcome of what your personality's going to be like and what kind of things will be interesting or not interesting to you. The same thing with the females. I don't want to downplay the nature-nurture debate. I think the nature-nurture debate, which has always been pulling against each other, I think that conflict is dead, because it's both the nature and the nurture that makes us who we are. Even some of the genetic changes from behavioral things and the way we're raised are really, really important. We want to understand the basic biology, don't we, Andy, underneath all of this?

Andy:
And it helps to just be more understanding and to not take things personally and to have a broader perspective, I think, which is helpful.

Louann:
Absolutely, I think especially for boys. As a mom of a boy, and I raised a teenage boy too, who's now 32, but I talk about his stuff somewhere in these books too. With his permission, of course, I told some of his childhood stories and his teen stories, but I so remember. Let's go to the onset of puberty for boys. Now, remember that the average age of the first wet dream is 13.5 in boys.

Andy:
Okay.

Louann:
That's how we identify when all the parts are working, when the testosterone, everything is working, 13.5, and that's plus or minus two years. When that happens, we know that testosterone curve is going skyrocketing. And the types of things it does for boys, not only does it, of course, make you have wet dreams and have all kinds of sexual fantasies, but it also makes you, every pair of breasts that walk by, or all of a sudden you start noticing female body parts in a whole different way. And that is so normal and natural, but boys often themselves feel like they've become some kind of perv or something.

Louann:
I remember one, they kind of feel like, "Oh, what's going on with my brain? All I can think about is sex. All I watch is girls' butts and breasts." That whole television screen in the back of the visual circuits in the male brain is turned on at that stage, and 13 males aren't really ready to handle that quite yet. And I really don't think that dads... Dads don't talk about this to their sons very much.

Andy:
No.

Louann:
Did your dad?

Andy:
Zero.

Louann:
I see you shaking your head. Your dad didn't tell you this, did he?

Andy:
No discussion. Yeah. You have a little sex ed in school or whatever. I think a lot of parents just rely on that, that "Oh, they're learning about all that stuff." It really is inadequate.

Louann:
Yeah. It was tough for me, because I was a single mom, of course, and I was raising a teen boy. I remember he came home from school one day and he said, "Oh, we had the sex talk. The PE teacher, the gym teacher gave us the sex talk today." And I said, "Oh, really? How was that?" And he goes, "Oh, it was okay," whatever. And I said, "Oh, that was the one where they talked about all the sexual fun? They talked about condoms and all that kind of stuff?" He said, "Oh no, they didn't talk about that."

Louann:
Here I am, a doctor, and I was blown away that the school chose not to teach them at 13 about condoms. It felt so wrong to me, because of sexually transmitted disease, all kinds of stuff, not only pregnant, all of this. It just seemed like that's the time. That's the time. You don't tell them once they're 19. It's too late. So I went out to the store and bought a three-pack of the Trojan. It was a three-pack. I brought it home. Then I also went to the grocery store and I got a medium, small-sized zucchini. I brought it home.

Andy:
Ah!

Louann:
And I showed him how to roll it down right and take it, whatever. And it was like, I knew it was really embarrassing for him. It was really embarrassing for me too, but it was really important to do. At any rate, I remember he had a friend a few years later that came by to borrow one of those. Yeah, exactly. That guy's now a Harvard lawyer, but anyway, we always laugh about that. But anyway, it's a good thing to do.

Andy:
We have this lady on the podcast, Amy Schalet, who does research comparing parenting in the Netherlands with parenting in America. It's really interesting in just how much more open parents are there, in talking about sex and letting the kids have sleepovers, but then talking with them or taking the boyfriend and the girlfriend to the sex store to get some condoms and discuss how does this all work and everything. I think we miss a big opportunity in America by not engaging about those things, or making kids feel like they have to sneak and do these things without having any input from adults.

Louann:
And it makes sex seem dirty and it makes it seem wrong. Anything that's not talked about, of course, especially for teens, they'll think there's something wrong about it and that they have to sneak and do it. We really miss an opportunity to validate all this, because it's going on in their brains anyway, like I talk about, because the hormones, they're skyrocketing. And the girls, three or four days before ovulation happens, their sex drive just goes skyrocketing too, and they're going to be flirtatious with boys and their hormones are going to be driving them to have sex too. I don't know. I think the American parents sometimes feel like if you don't talk about it, then it won't be a problem.

Andy:
Exactly. Yeah, yeah.

Louann:
It's very complicated. It makes teens in America also just discount that their parents have anything useful to teach them. It makes them just feel like we're ancient. We're ancient and we've forgotten what it's like to be-

Andy:
So out of touch.

Louann:

Yeah, out of touch. We can't imagine what it's like to be a teen now or something, which part of that is true, but there's a whole bunch of it that's not true, and it has to do with the sexual function that I talk about in the books.

Andy:
The testosterone is responsible for, I think like 2.5 times larger is sexual area in the male brain than the female brain.

Louann:
Right. There's an area that the technical name is a very easy name to remember. It's called the area for sexual pursuit, the area for sexual pursuit, and is part of the brain circuits for males. It's part of the brain circuits for females too, but it's 2.5 times larger in the male brain than it is in the female. And if you look at other types of rodents and stuff, you're looking at the male or female brain, it's like six times larger in a male mouse or something. Let's just say that it's a very important area. Like I said, Mother Nature gave you a job, guys. Your job is to search out fertile female. It's one of those things that you can't leave it to chance. Mother Nature couldn't leave that to chance that you were going to do that job, because you had to procreate the species.

Louann:
Also, it's important to understand the ancient wiring that we still have. We do live in civilized cultures, so we have all kinds of things that we need to learn to live in a society and a civilization, but this piece of that area of the brain, and that area of the brain is driven by that huge amount of testosterone. Remember, if our ovaries make 90% of our testosterone during our fertile years, from the ovary, from the little sack that's around the egg as well, it goes up the highest. If you draw a little curve where the highest part of the testosterone during the month is three or four days before ovulation, it's day 12, 13, 14. We count the menstrual cycle by day one of bleeding, is counted as day one of the cycle.

Andy:
Okay. Yeah.

Louann:
So day one of bleeding is day one of the cycle, and then you count forward. Usually, the first week of the cycle is the menstrual period, is the bleeding part of the period. And then as the second week comes along, the estrogen goes sky high. It really goes sky high, because the reason it goes sky high is it's going to cause ovulation. It's going to cause the egg to pop out and go down the fallopian tube and wait for that sperm that's swimming up to meet her. But that's why the sex drive is really ramped up along with the testosterone.

Louann:
For females, they feel much more flirty. They feel like they want to be much more attractive to males. There's a whole behavioral thing that, of course, you see in teen girls all the time, and you don't realize it's having this. The peak of it is three or four days before ovulation. I think it's good to know that. Remember, if the girl's on the pill or some kind of hormone contraceptive, when you're on the pill or something, it flattens out your sexual drive and you don't have this fluctuations, but the normal menstrual cycle is going to make you want sex right before ovulation. That's the second week. As soon as ovulation happens, then the egg pops out of that little sack. That little sack starts to make progesterone that then reverses all the stuff that the estrogen did.

Andy:
Ah!

Louann:
It's like in the brain, all these circuitries, the circuit comes out and neurons are connecting with each other throughout the female brain, particularly the area called the hippocampus. Not the hippopotamus, but the hippocampus. It's an area that's for memory, really important in all of us, but it really sprouts and grows a lot with all the estrogen in that second week. And then as soon as the progesterone comes after ovulation, it starts to tear down all those circuits. The female brain is being built up, built up, built up, and then torn down for the last two weeks of the cycle.

Louann:
And then remember, that one day or two days before the bleeding starts at the end is a time we call, da da da, PMS, the PMS time, because all the hormones are just dropping like a rock. They're decreasing very quickly and that's what signals the menstrual period to start, but it causes the brain, we call it in my clinic, Andy, we call it the crying over dog food commercials, because it's almost like you can just go into tears or boohoo over anything. Anything can hit you as being something that's... Or crying and tears or emotional, or the other way too. You can feel like something that's said to you that's just a little bit... You take it wrong. You take it wrong or take it a little bit wrong, and you're angry and irritable and you think your boyfriend is like Frankenstein or whatever.

Louann:
It's just you're feeling very sensitive to all kinds of emotions during that 24 to 48 hours. About 90% of women have some of that in their fertile years at the end of their cycle. It doesn't seem to have any purpose, not much of a purpose, but I tell couples and I teach the women that it's a time that don't just sweep some argument with your partner under the rug at that time. But I tell the guy that he's supposed to write it down on a little piece of paper and then remember it three or four days later when she's feeling at her best self again, because it's silly to start an argument when someone's just ready to cry over the drop of a hat.

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Ep 194: Sex Hormones and Your Teen’s Brain
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