In 2013, professional sprinter Dutee Chand was banned from competing as a female athlete. She wasn’t accused of doping, and she wasn’t accused of not being a woman—she was born and raised as a girl. Instead, her hormones were at fault.

Chand’s natural testosterone levels fall into a male range, and according to international regulations, she can’t compete again until her testosterone lowers to a more ladylike level—a process that would require drugs or surgery. Chand refuses, and in March she challenged the ban. Switzerland’s Court of Arbitration for Sport is expected to come out with a decision this summer.

A number of other female athletes have had their gender called into question as a result of the testosterone rules, most notably Caster Semenya, who had to undergo sex-testing after winning the women’s 800 meter race in the 2009 World Championships.