Perhaps you've heard the tragic story of David Reimer. Born in Winnipeg, Manitoba, Canada in 1966, David was the victim of a botched circumcision that left his penis charred beyond surgical repair. His parents Ron and Janet, no doubt beside themselves, were confused about the best way to proceed. Then, one day, they saw a man named Dr. John Money on television. Money was talking about his theory of "gender neutrality," which states that "gender identity" is learned rather than innate. The idea was that the sexes were the same except for the superficial physical differences; this implies that if...