“A bulletproof case that sexual diversity exists in the natural world…The Sexual Evolution is a thoughtfully and delightfully written book full of illuminating and entertaining information that will be new to most readers. At a time when ignorance and misinformation about sex, gender, reproduction, and intimacy abound, we could all benefit from reading this research-packed tour.” — Science

 Evolutionary biologist Nathan H. Lents knows what makes humans unique—and as he reveals in this fascinating work of pop science, 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 readers on a journey through the animal world, exploring the evolutionary biology that reveals 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 the full spectrum of gender and sexuality. 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 biology of sex, The Sexual Evolution is the rare book 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.

• The Science of Sexuality: Go beyond cultural debates to explore the biological story of sex, from the evolution of gametes to the complex behaviors of our closest animal relatives.
• Gender Diversity in Nature: Discover how animals have been experimenting with gender expression for millions of years, featuring sex-switching clownfish, multiple male genders in sunfish, and more.
• Same-Sex Behavior in the Animal Kingdom: From lesbian albatrosses to gay rams and the famously queer bonobos, see how homosexual behavior is not only natural but serves a crucial purpose in social animals.
• A Rebuttal to Bigotry: Arm yourself with a bulletproof, research-packed case that demolishes the claim that sexual diversity is “unnatural” and affirms that when it comes to evolution, diversity wins.