A Pulitzer Prize-winning journalist offers scientific proof of what we've suspected all along - men and women are different! Did you know that male testosterone levels drop when the men are in happy marriages? Does it surprise you that young female children who are in day-care are apt to be more secure than those kept at home? Would you believe that anthropologists classify American society as mildly polygamous? Drawing on disciplines that include evolutinary science, anthropology, animal behaviour, neuroscience, psychology, and endocrinology, Deborah Blum goes beyond the headlines and the hype to explore matters from the link between immunology and sex to male/female gossip styles. The results are intriguing, startling and often very amusing.