The evolutionary biology of testosterone: how it shapes male development and sex-based behavioral differences, | Carole Hooven, Ph.D.

**Peter Attia, MD** (0:11)
Hey everyone, welcome to the Drive Podcast. I'm your host, Peter Attia. This podcast, my website and my weekly newsletter all focus on the goal of translating the science of longevity into something accessible for everyone. Our goal is to provide the best content in health and wellness, and we've established a great team of analysts to make this happen. It is extremely important to me to provide all of this content without relying on paid ads. To do this, our work is made entirely possible by our members, and in return, we offer exclusive member-only content and benefits above and beyond what is available for free. If you want to take your knowledge of this space to the next level, it's our goal to ensure members get back much more than the price of a subscription. If you want to learn more about the benefits of our premium membership, head over to peterattiamd.com/subscribe. My guest this week is Carole Hooven. Carole is a human evolutionary biologist. She is a former Harvard lecturer and non-resident senior fellow at the American Enterprise Institute. Her research focuses on testosterone, sex differences and behavior. She holds a Ph.D. in Biological Anthropology, now Human Evolutionary Biology, from Harvard University and is the author of T. The Story of Testosterone, The Hormone That Dominates and Divides Us. In this episode, we discuss how prenatal testosterone shapes the male body and brain, turning genetic signals into thousands of developmental changes that underlie later sex differences, critical hormone surges and why they matter for lifelong behavior, DHT, androgen receptors and rare natural experiments, for example, 5-alpha reductase deficiency, that reveal how external genitalia and the prostate masculinize, distinct male and female aggression styles, direct physical confrontation versus indirect or relational tactics, and the evolutionary logic behind each, why modern life changes but doesn't erase ancient drives like male competitiveness and the trade-offs of trying to suppress them, testosterone, aging, and hormone therapy for both sexes, including Carole's personal experience after surgical menopause, and the cultural debate over masculinity and the cost of denying biological sex differences, a theme of Carole's forthcoming book. So without further delay, please enjoy my conversation with Carole Hooven.
Carole, thank you so much for coming out to Austin. Great to meet you in person.

**Carole Hooven, Ph.D.** (2:43)
Thank you so much for having me. I'm thrilled to be here.

**Peter Attia, MD** (2:47)
This is a topic that we talk a lot about on the podcast, but usually from a pretty narrow lens, which is in the form of replacement. We talk about hormones, both in men and women, sex hormones, and we talk about how they wax and wane as an individual ages. We obviously then talk about the medical use of them, but I don't think we've spent any time understanding the more basic fundamentals of these hormones, the role they play in our evolution. And anecdotally, I'll just share with you kind of the observation that any parent probably has if they have male and female children. My first child was a girl, and my wife and I very, very stupidly and arrogantly thought we were the perfect parents because like she was so well-behaved, and we were like, what do all of these other parents with their boys running around misbehaving, like what are they doing wrong? How could we teach them how to be as good as we are? I mean, we didn't actually say that, but there was undoubtedly an annoying smugness to us. And if you believe in a god, that god smacked us into our place with two boys that followed, who were for all intents and purposes, treated the same way, socialized the same way, and there is a level of aggression in them, a fury in them that I've never seen, probably unless I were to go back and hear stories of what my mom said I was like.

**Carole Hooven, Ph.D.** (4:18)
How old are your boys now?

**Peter Attia, MD** (4:20)
Eight and almost 11

**Carole Hooven, Ph.D.** (4:22)
Okay.

**Peter Attia, MD** (4:23)
I wouldn't say they're a different sex. I would say they're a different species.

**Carole Hooven, Ph.D.** (4:26)
Yeah, I was just going to say that.

**Peter Attia, MD** (4:27)
Yeah.
So, all of that is to say, I don't feel we did anything different, and yet they couldn't be more different. And I appreciate that that's not going to be the case for every parent. What I hope to learn is how much testosterone has to do with that, because I also am under the impression that at this age, the testosterone levels wouldn't be that much different. And I understand and we'll probably talk about the differences in testosterone levels during the embryologic phase, because obviously that led to the differences. But anyway, with that as backdrop, how did you get interested in this topic?