South African middle-distance star Caster Semenya faces being banned from female races should new IAAF rules come into effect in November.
Semenya, who won women's 1500m gold at the Commonwealth Games in Australia on Tuesday, has long been the centre of controversy within athletics because of her hyperandrogenism, a condition which sees her produce excessive levels of androgens - male sex hormones including testosterone.
The new policy, which is set to be enforced from November 1, would prohibit women with a high level of testosterone from competing in track events between 400 and 1500m.
Should it come into force Semenya, winner of Olympic 800m gold in 2012 and 2016 among a host of medal-winning performances, would either have to reduce her hormone levels or leave the sport.
The victory on Tuesday was her biggest over 1500m, when she broke the Commonwealth Games record in setting a winning time of four minutes, 00.71 seconds.
She will bid for a golden double in the final of the 800m on Friday after winning her heat on Thursday.
The IAAF previously adopted a new code of rules on hyperandrogenism in 2011, setting an upper limit for testosterone, but their ruling was reversed in 2015 after a challenge from Indian sprinter Dutee Chand.
Judges then ruled that the IAAF had not produced sufficient evidence that high levels of testosterone could improve performance, and the Court of Arbitration for Sport (CAS) asked for more to be provided.
That evidence has now been submitted to CAS and the sport's governing body is awaiting a response.
