Few athletes have been as blessed and cursed as Caster Semenya. All that the 28-year-old South African has ever done is run as fast as her legs could carry her—fast enough to win back-to-back Olympic gold medals over 800 metres. But her remarkable body has also drawn ridicule, speculation and a decade of investigation.
In 2009, when she breezed to a World Championship title, the International Association of Athletics Federations (iaaf), the sport’s governing body, began examining whether she might be intersex—an umbrella term for people with developmental conditions affecting the genitalia and gonads. To protect her privacy, the findings are unpublished. The iaaf has since been in a regulatory tussle about whether Ms Semenya must adjust her testosterone levels to compete as a woman. On May 1st the Court of Arbitration for Sport (cas), an international court for sports, ruled against her. Its decision covers only athletes with one of a group of syndromes known as 46,xy, which means that a person with a maley chromosome and high testosterone does not develop male genitalia. The ruling has implications far beyond Ms Semenya’s sport—and indeed, beyond sport itself.