Caster Semenya has lost her landmark legal case against the IAAF, athletics' governing body.
The South African had challenged the IAAF's proposal to restrict testosterone levels in female runners in certain events.
But in a surprise decision, announced by the Court of Arbitration for Sport (CAS) after three judges spent almost a month deliberating over the complex and highly contentious case, the 2016 Olympic gold medallist must now take medication to continue running on the international stage.
Semenya had taken the IAAF to court over its plans that required female athletes with differences in sexual development (DSDs) – some of whom are born with male testes – to take hormone suppressants.
The 28-year-old argued that the policy was discriminatory, unfair, and potentially posed a health risk.
Semenya's gender has been under scrutiny for the last decade after she broke onto the scene as a teenager.
Here is all you need to know about Semenya, the importance of her case, and why she remains one of sport's most controversial figures.
Profile
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Full name: Mokgadi Caster Semenya OIB
DOB: 7 January 1991 (28 years old)
Place of birth: Pietersburg (now Polokwane), South Africa
Sport: Athletics
Distance: Middle - 400m, 600m, 800m, 1000m, 1500m
Is she any good?
Not half.
Semenya is considered one of the most dominant and successful stars in modern athletics.
At 28 years old, she has won each of her previous 29 races in her party piece 800m event, and is a three-time world champion and double Olympic gold medallist over the distance.
A two-time Commonwealth gold-medallist, Semenya’s meteoric rise to success was apparent when she first became World Champion in 2009, just a year after first competing at junior level.
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Why is she under scrutiny?
Following glory in the World Championships in 2009, Semenya's gender has come under scrutiny.
After breaking her previous personal best at 800m by four seconds just a month earlier at the African Junior Championships, her rapid athletic progression and development was widely quesitoned.
She was obliged to take a sex verification test by the International Association of Athletics Federations (IAAF) to ascertain whether she or not she was indeed female, and the results have subsequently proved Semenya carries higher-than-normal levels of testosterone.
Why is this important?
In April 2018 the IAAF introduced a new ruling which would require females with differences in sexual development (DSDs) to reduce their testosterone levels, should they wish to compete in international events between 400m and a mile.
So what is her case?
Semenya challenged the IAAF’s fresh ruling on DSD athletes in the Court of Arbitration for Sport (CAS) in February, claiming these rules discriminated against her as a DSD athlete, and that it isn’t clear how much DSD athletes benefit from naturally higher levels of testosterone.
What could happen?
There are a number of possible outcomes, if you hadn’t already figured them out.
Either Semenya wins the right to compete as a woman, or she is overcome by the IAAF and is, as a result, required to reduce her testosterone levels or compete at a longer distance.
What is the backlash?
If Semenya is victorious, she will likely continue to dominate middle-distance running for years to come.
However this will lead to CAS and the IAAF having another huge case to deal with, as transgender athletes, would contest why they have been made to alter their testosterone levels before competing, while DSDs have not.
In addition to this, there are suggestions the IAAF could introduce an ‘open’ competition category where men and women effectively compete against each other, on top of a ‘protected’ category based solely on hormone levels and not gender.
This however, would naturally then be sure to open further fields of contest and controversy.
