Book excerpt: Go beyond the headlines and the hype to get the newest findings in the burgeoning field of gender studies. Drawing on disciplines that include evolutionary science, anthropology, animal behavior, neuroscience, psychology, and endocrinology, Deborah Blum explores matters ranging from the link between immunology and sex to male/female gossip styles. The results are intriguing, startling, and often very amusing. For instance, did you know that. . . • Male testosterone levels drop in happy marriages; scientists speculate that women may use monogamy to control male behavior • Young female children who are in day-care are apt to be more secure than those kept at home; young male children less so • Anthropologists classify Western societies as "mildly polygamous" The Los Angeles Times has called Sex on the Brain "superbly crafted science writing, graced by unusual compassion, wit, and intelligence, that forms an important addition to the literature of gender studies."