Semenya lost a case last week that challenged a new rule by the International Association of Athletics Federations (IAFF) that requires female athletes with naturally high testosterone to take suppressants in order to compete in certain women’s races.
Mosier argues that, like fellow Olympic champion Michael Phelps, Semenya has found the sport she was meant for.
“We know that Michael Phelps was suited to be a swimmer but he may not have been a great sprinter, so he found the sport that he was made for just as [Caster] Semenya has found the sport she was made for,” he told Hill.TV during an interview that aired on Monday.
“They are just targeting one element of what might make an athlete a good athlete,” he added, referring to Semenya's above average testosterone levels.
The ruling comes amid a heated debate over how much hormones can enhance athletic ability and whether it should be monitored to reduce unfair advantages. While some argue that higher levels of testosterone can give athletes a competitive advantage, others, like Mosier, have argued that this notion is arbitrary and unscientific.
"In order to have participation in sports as we know it, it’s a very binary system, so we have the male and female category," he told Hill.TV. "The issue here is that we have a sort of arbitrary ruling about who is male and who is female."
Semenya has faced scrutiny about her gender ever since she won gold in the 800-meter races at the 2012 and 2016 Olympics, but 28-year-athlete from South Africa has made it clear that she won’t give up the fight.
“Be you for you,” she tweeted just days after the new ruling.
The court’s decision is expected to take effect on May 8.
— Tess Bonn