 The book was co-authored with my wife, Kassil Dejeta, who is in the audience, so I have to get that out right, right off the bat. I'm not gonna try to summarize the book in five minutes, so I'm just gonna talk about the most central question that we ask in the book, which is, why is sex such a big deal for human beings? Why is it such a problem? We know it's a problem, right? Look in the newspapers, look on the TV, you see it's a problem everywhere we turn. So the standard narrative of human sexual evolution posits that since the beginning of time, men have been trading goods and services for sexual fidelity from the female, right? As a way of assuring their paternity, so their investment in these children is safe. They know it's my child that's getting this meat and this protection and this shelter and whatever it is that I'm investing. Now, if we evolved the way the standard narrative argues in these nuclear families, then we shouldn't be having a big problem with sex. What Cassilda and I argue in the book is that in fact, our ancestors evolved in the context of sperm competition, which will not be an event at this year's Olympics. I just wanna make sure everyone understands. Sperm competition refers to when the, let's say the field of battle on which men struggle for the access to females for the right or the ability to fertilize a female and pass their genes on is shifted from the individual male to the sperm cells. So the field of battle moves from the outer world that we all live in to the woman's reproductive tract. If several different males have sex with any given female in an ovulatory cycle, the sperm cells themselves will battle out to see who gets to which genes go on into the future. In the chart here, you can see very briefly, I won't talk about too much here, but you can see on the right side of the chart, you've got gorillas, orangutans and gibbons which are not promiscuous breeders. Look at the size of those testicles and look where they are, they're inside their body. A full grown silverback gorilla has testicles the size of kidney beans and his penis is the size of my little finger, fully erect. Sorry if there are any gorillas in the audience, I just, it's true. On the other hand, you've got promiscuous breeders like chimps, bonobos and human beings if you follow our logic, who have much larger testicles. The testicles of chimps and bonobos are roughly the size of AAA chicken eggs. Obviously humans aren't quite up to chicken egg standards but our penis, good news, is the longest and thickest of any of the primates. So these are anatomical indications of sperm competition in our past. Another indication is behavioral. Look at human sexuality, look at how wasteful it is. Our sex act to birth ratio is about 1,000 to one. For those of you whose ratio is under 1,000 to one, other people in the room are making up for you, don't worry about it. The gorillas sex act to birth ratio is about 10 or 15 to one at best, right? And that's more typical of mammals. Mammals generally don't have sex unless the female's ovulating because it's dangerous. While you're off humping in the bushes, leopards are coming around and they hear you and they smell you, you have to be careful. So biologically it doesn't make sense to be having all this sex. Human beings, we have sex, we have sex solo, we have sex with men, with women, we have sex with vacuum cleaners, with vibrators, in Japan with robots, we're having sex constantly, right? Lots of us, like myself, have never had any children. So what's going on? The point is that we evolved not to have sex be primarily about reproduction. Human sexuality is primarily about establishing and maintaining complex social networks. That's what human sexuality is about. That's what bonobo sexuality is about. That's what dolphin sexuality is about. So this is something that's common in highly intelligent, highly social species. So it's not as radical an idea as it may seem. Now we see in fashion, what does that look like to you? To me, that looks like swollen chimpanzee genitalia, okay? Maybe that's just me. And it's not isolated in 19th century British fashion, either, this is the butt bra. What is going on here? Those of you who say, oh, we're not animals, check out the butt bra. Tell me we're not animals. Okay, and if the chart was a little dry for you, here you have the gorilla, the bonobo, and the Italian. The Italian, I have to tell you, I have 47 seconds left, quick story. The Italian is a good friend of ours who lives in India. And I always say in presentations, oh, he'll never know, right? A few days ago he sent me an email, he said, I watched your presentation in Australia, you used my picture! It's fine, it's fine. Anyway, he's obviously closer to the bonobo than he is to the gorilla, that's all I'm saying. The final thought I wanna leave you with is that our book does not argue, and I'm not here today to argue that long-term sexual monogamy is a mistake. What I'm trying to say is that it's like vegetarianism. It can be ethical, it can be healthy, it can be wonderful for the environment, it can be great in so many different ways, but the fact that you've chosen to be a vegetarian does not mean bacon suddenly stops smelling good. Thank you.