Biologist Nathan Lents joins Science Quickly to explore the vast sexual diversity found across the animal kingdom. His new book, The Sexual Evolution: How 500 Million Years of Sex, Gender, and Mating Shape Modern Relationships, challenges the binary framework that has long shaped biological research, arguing for a more accurate and inclusive view of sex and gender. From alternative reproductive strategies to overlapping traits, this episode reveals how nature defies neat categories—and why science should, too.

Recommended Reading

Here’s Why Human Sex Is Not Binary

This Backyard Bird Has a Lot to Teach Us about Sex Variability

The Sexual Evolution: How 500 Million Years of Sex, Gender, and Mating Shape Modern Relationships, by Nathan Lents. Mariner Books, 2025

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Science Quickly is produced by Rachel Feltman, Fonda Mwangi, Kelso Harper and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck fact-check this show. The theme music was composed by Dominic Smith.


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