A scientific paper published Monday found that women who produce higher-than-normal amounts of testosterone have up to a 4.5 percent advantage over their competition on the track, evidence the sport's governing body will use to potentially sideline Olympic gold medalist Caster Semenya and others with so-called intersex conditions.

The International Association of Athletics Federations will use the new study in its appeal to the Court of Arbitration for Sport, which suspended an IAAF rule that enforced a limit on female athletes' naturally occurring testosterone levels. The appeal will not affe...