We talk with evolutionary biologist Dr. Nathan Lents, about his book “The Sexual Evolution: How 500 Million Years of Sex, Gender, and Mating Shape Modern Relationships”. The book explores sex, gender, mating, and more in dozens of species -- from insects, to birds, to fish… to the primates most closely related to us humans. Lents is a Professor of Biology at John Jay College of The City University of New York. A version of this conversation originally aired March 2025.