Why the Caster Semenya sex eligibility battle confounded sports for 16 years and still isn’t over

How the rules work

Track and field’s regulations depend on the conclusion that higher testosterone gives rise to an athletic advantage, though that has been challenged in just one of the many complicated details of Semenya’s case.

To follow the rules, DSD athletes must suppress their testosterone to below a threshold that World Athletics says will put them in the typical female range. Athletes do that by taking daily contraceptive pills or using hormone-blocking injections and it’s checked through regular blood tests.

Track first introduced a version of its testosterone regulations in 2011 in response to Semenya and has made them stricter over the years. The current rules require athletes affected to reduce their testosterone for at least two years before competing and throughout competitions, effectively meaning elite DSD runners would be constantly on medication to stay eligible for the biggest events like the Olympics and world championships.

That has troubled medical experts and ethicists, who have questioned the “off-label” use of birth control pills for the purpose of sports eligibility.

Semenya is not alone

While Semenya is the only athlete currently challenging the regulations, three other women who have won Olympic medals — Francine Niyonsaba of Burundi, Margaret Wambui of Kenya and Christine Mboma of Namibia — have also been sidelined by the rules.

The issue came to a head at the 2016 Olympics in Rio de Janeiro, Brazil, when Semenya, Niyonsaba and Wambui won the gold, silver and bronze medals in the 800 meters when the rules were temporarily suspended. Supporters of the ban cited that result as evidence they had an insurmountable advantage over other women.