by Matt Ridley
Review: Why do we have sex? One of the main biological reasons, contends Ridley, is to combat disease. By constantly combining and recombining genes every generation, people "keep their genes one step ahead of their parasites," thereby strengthening resistance to bacteria and viruses that cause deadly diseases or epidemics. Called the "Red Queen Theory" by biologists after the chess piece in Lewis Carroll's Through the Looking-Glass which runs but stays in the same place, this hypothesis is just one of the controversial ideas put forth in this witty, elegantly written inquiry. Ridley, a London-based science writer and a former editor of the Economist , argues that men are polygamous for the obvious reason that whichever gender has to spend the most time and energy creating and rearing offspring tends to avoid extra mating. Women, though far less interested in multiple partners, will commit adultery if stuck with a mediocre mate. In Ridley's not wholly convincing conclusion, even human intellect is chalked up to sex: virtuosity, individuality, inventiveness and related traits are what make people sexually attractive.