Caster Semenya is to be forced to take medication to lower her testosterone levels or move up to longer distances as a result of new rules by the International Association of Athletics Federations (IAAF).
The IAAF has published a revised version of its hyperandrogenism rules which will prevent women with the condition, which sees them produce excessive levels of androgens - male sex hormones including testosterone, from running distances from 400m to the mile.
The new ruling affects female athletes who have a 'Difference of Sexual Development' - that means testosterone levels 5 nanomols or above.
To comply and be able to race they must be recognised by law as female or intersex, blood testosterone levels must be lower than 5 nanomols for a period of at least six months (control with hormonal contracepties) and maintain blood testosterone levels of below 5 nanomols continuously to be eligible to race.
The rules come into effect on November 1.
The original rules, introduced in 2009, came as a response to concerns about female athletes, including the two-time 800m Olympic champion, with naturally high levels of testosterone having an unfair competitive advantage before they were suspended by the Court of Arbitration for Sport in 2015.
The CAS ruling resulted from a legal challenge by Indian sprinter Dutee Chand and invited the IAAF to commission scientific research to justify its testosterone ceiling for female athletes.
Semenya, who had a gender verification test at the 2009 World Championships after winning 800m gold - the first of three world titles at the distance, has competed under intense scrutiny during her career and most recently claimed an 800m and 1500m double at the Commonwealth Games in Australia.
"This is not about cheating. No hyperandrogenic athlete has cheated," IAAF president Lord Coe said on the subject last month.
"This is about our responsibility as a sport federation to ensure a level playing field. It is for us to decide the rules, to draw the lines for competition.
"We choose to have two classifications for our competition - men's events and women's events. This means we need to be clear about the competition criteria for these two categories.
"We have always believed that testosterone, either naturally produced or artificially inserted into the body, provides significant performance advantages."