The YouTube source features Professor Paul Bloom discussing the multifaceted nature of sex, highlighting its perceived importance versus the minimal time spent on it. He explores sex differences from a biological and evolutionary perspective, including physical attributes, aggression, and sexual choosiness, using parental investment theory to explain many observed variations across species and in humans. The lecture also touches on the universal aspects of sexual attractiveness, such as cues for youth and health. Finally, Bloom addresses moral implications and the inevitability of biological predispositions, emphasizing that biology does not dictate morality or fate, and tackles the enduring puzzle of exclusive homosexuality.