Why Don’t You Have Sex With Your Sister? - Dr Debra Lieberman - #1041

Jan 3, 2026 · 1h 08m

Dr. Debra Lieberman is an evolutionary psychologist, professor, and researcher. Why don’t we feel sexual attraction toward our siblings or close family? Evolution seems to have hard-wired the brain to prevent inbreeding, a pattern shared with many other animals. So how does this mechanism work, and what are the moral or ethical arguments surrounding incest? Expect to learn why evolution has designed you to not want sex with your sister, how animals actually detect who their relatives are, what the high level explanation is for why humans don’t want sex with their kin, the moral argument if it is okay if two adult siblings had consensual sex, how big the actual genetic risk is for first cousins, what crying adn tears actually communicate from an evolutionary perspective and much more… Timestamps: (0:00) Why Don’t We Want to Have Sex With Our Siblings? (7:57) What Triggers Our Incest Avoidance Mechanism? (19:04) Is Incest Disgust a Moral Pressure? (27:19) How Only Children Make Sense of Incest (31:11) Why Is Incest P**n So Popular? (37:19) Why Do We Cry? (52:53) What Happens When No One is Watching (58:07) Why We Use Tears to Convey Emotions (01:06:30) Where to Find Debra Sponsors: S…

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