Aces Fox, a former competitive track and field sprinter, was raised as a girl and won two junior Olympics gold medals competing against both boys and girls. At 19, Fox found out they were intersex, with two sets of DNA.
Now, the IOC plans to require testing for adults and minors—who may discover life-altering results at a young age.
The youngest girl to compete in the 2024 Summer Olympics was 11 years old. The youngest girl Winter Olympian this year was 15. Under the new rules, both girls will be tested before their next Olympic opportunity.