Is gender really as straightforward as we would all like to think? What is it that makes anyone a man or woman? A female athlete is the subject of international controversy surrounding her right to compete as a woman; a pre-pubescent girl demands medical treatment to prevent the onset of female puberty; a school-age boy lives his life as a girl with his parent's support. Questions about gender and identity are confusing and often generate controversy. More and more, stories about children "identifying" as the opposite sex, and parents allowing them to live their lives as the alternate, or...