The Sexual Evolution

How 500 Million Years of Sex, Gender, and Mating Shape Modern Relationships

By: Nathan H. Lents

Narrated by: Daniel Henning

“Enthralling . . . Lents gleefully tears down cis, hetero, and monogamous norms, outlining surprising case studies that give the lie to restrictive conceptions of gender and sex. The result is an indispensable glimpse into the queerness of animals.”—Publishers Weekly (starred review)

Evolutionary biologist Nathan H. Lents knows what makes humans unique—and it’s most definitely not our sexual diversity. A professor at John Jay College, Lents has spent his career studying what makes us, well, us, and contrary to what the culture warriors want people to believe—diverse sexual behavior is not a new development, or even a human one. It didn’t just emerge from a progressive culture; it’s the product of billions of years of evolutionary experimentation throughout the animal kingdom. It’s not a modern story, a Florida story, or even a human story. It’s a biological story.

In The Sexual Evolution, Lents takes listeners on a journey through the animal world, from insects to apes, revealing what the incredible array of sexual diversity can teach us about our own diverse beauty. Nature, it turns out, has made a lot of space for diverse genders and sexual behaviors. And why? Because when it comes to evolution—diversity wins. This is not just a political or social message, instead it’s rooted in science and cultivated from understanding the full breadth of sexuality that exists throughout the world.

With shades of both Frans de Waal and Esther Perel, Lents’s storytelling is as fascinating as it is topical, offering eye-opening stories about the diversity of animal life, while relating it to our own sexual journey as a species. At once a forceful rebuttal to bigotry and a captivating dive into the secret sex lives of animals, The Sexual Evolution is the rare book of pop science that leans into the controversy. Sex, the reactionaries say, should only be for procreation between a man and a woman, anything else goes against nature. Well, nature would like a word with them.

©2025 Nathan H. Lents (P)2025 HarperCollins Publishers