Providing a fascinating look at the science of sex and what makes people male or female, this book explains dozens of intersex conditions—such as hermaphroditism, Klinefelter syndrome, and androgen insensitivity syndrome—and includes personal interviews with people living with these conditions telling their surprising and often heart-wrenching stories. Even doctors and scientists are not entirely sure if external genitalia, internal sex organs, chromosomes, DNA, environment, or some combination define a person's sex, but this examination shows that sex is not an either-or proposition: not girl/boy, XX/XY—there are babies born XYY, XXX, or with any dozen or more known variations in the X or Y chromosomes. The history and the current treatment for intersex conditions as well as the options that are available today for the ambiguous child are covered in this captivating account that truly shows what it means to be human.