Dr. Marc Breedlove, PhD, is a professor of neuroscience at Michigan State University and an expert on how hormones shape brain development and sexual orientation. We discuss how prenatal testosterone impacts whether someone is romantically attracted to men or women later in life, and what correlates of sexual orientation — such as finger-length ratios — tell us about the role of hormones in brain and psychological development. We also discuss why the number of older brothers a male has biases sexual orientation. Throughout, we explain how nature and nurture interact to shape male-female differences, behavior, and romantic partner choice. Thank you to our sponsors AG1: https://drinkag1.com/huberman David: https://davidprotein.com/huberman Rorra: https://rorra.com/huberman Function: https://functionhealth.com/huberman Timestamps (00:00:00) Marc Breedlove (00:03:24) Hormones & Sexual Orientation (00:07:37) Prenatal Testosterone, Finger Ratio, Men & Women Differences (00:14:08) Sponsors: David & Rorra (00:16:46) Finger Ratios, Prenatal Testosterone, Gay & Straight Men/Women (00:23:57) Mice & Sex Differences, Androgens (00:26:54) Brain Differences & Sexual Orientation (00:33:52) Group vs Individual Differences, Height Analogy; Bisexuality (00:36:57) Brain Development, Hormones & Behavior; Brain Plasticity (00:42:52) Sponsor: AG1 (00:44:16) Sexual Behavior, Libido (00:51:37) Gay Rams, Brain Differences (00:58:00) Aversion Pathway, Men vs Women, Same-Sex Partner (01:06:58) Congenital Adrenal Hyperplasia (CAH), Intersex Phenotypes (01:13:55) Androgen Insensitivity Syndrome (AIS) (01:18:14) Sponsor: Function (01:19:25) Gay Men & Older Brothers, Maternal Immunization Hypothesis (01:32:55) CAH Carriers, Advantage, Stress Tolerance (01:35:41) Birds & Sexual Differentiation, Gynandromorphs (01:41:32) Anabolic Steroids, Hypersexuality; Adult Brain Plasticity (01:45:31) Age & Testosterone Decline; Sexual Orientation & Activities (01:53:14) Marc's Academic Journey, Ozarks, Luck (02:02:35) Exploration; Kids & Sex Differences (02:08:47) Zero-Cost Support, YouTube, Spotify & Apple Follow, Reviews & Feedback, Sponsors, Protocols Book, Social Media, Neural Network Newsletter Disclaimer & Disclosures Learn more about your ad choices. Visit megaphone.fm/adchoices