Dear Caster Semenya, When you compete at the Olympics this summer, you won't be able to hear me cheering for you -- I will be thousands of miles away, and you will be in the center of the Olympic stadium in Brazil. I don't need to tell you that your contest is contested. Many of those watching you -- from sports pundits to spectators -- have grumbled about your right to compete ever since you won at the 2009 world track and field championship. They have questioned whether you, the fastest woman in the world, are actually a woman. They have contended that you have too much testosterone to participate fairly with other women. Your competitors have sneered at your talent and, with it, your personhood. "These kind of people should not run with us. For me she's not a woman. She's a man," your Italian rival Elisa Cusma told a New York Times reporter after your 2009 victory. "Just look at her," said Mariya Savinova, your Russian challenger. Years later, the...