"In this multilayered exploration of gender biology, The Sexual Evolution, Nathan Lents takes us on a wonderfully thoughtful journey through some of today's most challenging scientific terrain. The result is a book that expertly balances the complexity of the issues and the compassion needed to navigate them, in other words, exactly the kind of guide to the subject that we all need today."  - Deborah Blum, Pulitzer-prize winning author of The Poison Squad: One Chemist's Single-Minded Crusade for Food Safety at the Turn of the 20th Century
“A lot of people seem to think they know what science says when it comes to sex. Well, Nathan Lents has news for them. Read this book—it’s fascinating, charming, and eye-opening, with lovely ink drawings that bring the animals in its pages to life. It dispels misconceptions about life in the animal kingdom and our place in it, but most importantly it shows clearly that nature’s beautiful sexual diversity extends to all living things—especially humans.”
- Joan Roughgarden, Professor Emerita of Biology, Stanford University, author of Evolution’s Rainbow and The Genial Gene
“An excellent, easy-to-read, science-based summary of what we know about the incredible array of sexual diversity among other animals. A fascinating and eye-opening book.”  - Marc Bekoff, author of Dogs Demystified: An A-to-Z Guide to All Things Canine and The Emotional Lives of Animals.
“A refreshing read that puts human sexuality in perspective without cultural dogma and indoctrination. With eye-opening stories of animal behavior, Lents highlights the fundamental role of sexual diversity for all animals—including humans. Humans are sexual creatures, but we are sexual in so many ways that do not conform to Western notions of sexuality. The Sexual Evolution tells this story, and so much more, with the clarity and urgency that it so justly deserves.” - Darrel Ray, Ed.D., author of Sex and God: How Religion Distorts Sexuality, Founder and President, Recovering from Religion
“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)
“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
“At a time when diversity is fast becoming a dirty word, The Sexual Evolution provides a powerful argument about why diversity not only exists, but wins. Lents' scholarly tome never lectures but guides the reader through a glorious array of gender and sexual diversity from across the animal kingdom, with authority and humour. An important addition to this important genre. My copy of this book will be read many times.”  - Lucy Cooke, author of Bitch
"Leave it to Lents to remind us that yes, we have sex for many reasons, and yes, they’re often funny as hell. Bravo!” - Cat Bohannon, author of EVE: How the Female Body Drove 200 Million Years of Human Evolution