QUOTE : What if we looked beyond reproduction altogether? After all, genitalia, contrary to Darwin’s claim, do far more than just fit together mechanically. They signal, symbolize, and titillate—not just to a potential mate, but to other members of a group. In humans, dolphins, and beyond, sex serves richer and more complex purposes than solely the transfer of sperm from one party to another. It can be used to strengthen friendships and alliances, make gestures of dominance and submission, and as part of social negotiations like reconciliation and peacemaking, argues ecologist and evolutionary biologist Joan Roughgarden, author of the 2004 book Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People.