Justin Garcia (The Intimate Animal: The Science of Sex, Fidelity, and Why We Live and Die for Love) is an evolutionary biologist, researcher on sex and relationships, and Executive Director of the Kinsey Institute. Justin joins the Armchair Expert to discuss the unique quality that human sex is so tied to our social behavior, the physiological constraints on mating in other animals, and how sexually we are like magpies. Justin and Dax talk about why gorillas have really small testes, how the pandemic resulted in couples weathering the storms of relationship conflict, and an evolutionary explanation for how difficult it is to choose mates on a dating app. Justin explains how collecting hormone samples at a brothel in Las Vegas led him to write his book, why there’s no requirement to enter a relationship fully healed, and the social science behind love, partnership, fidelity, and heartbreak. Follow Armchair Expert on the Wondery App or wherever you get your podcasts. Watch new content on YouTube or listen to Armchair Expert early and ad-free by joining Wondery+ in the Wondery App, Apple Podcasts, or Spotify. Start your free trial by visiting wondery.com/links/armchair-expert-with-dax-shepard/ now. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.