Many feel as though the ruling is simply unfair.
Caster Semenya is an accomplished Olympic athlete who has competes as a runner for South Africa. Over the past few years, Semenya's status as an Olympic athlete has been shrouded in controversy thanks to a new rule that forces female athletes with high testosterone levels to take hormonal contraception. Semenya is hyperandrogenous and her testosterone levels are much higher than most women, including her competitors. The International Association of Athletics Federations has ruled that if she wants to compete in the 2020 Tokyo Olympics, she'll have to take testosterone-lowering medication as the IAAF believes she would have a competitive advantage otherwise.
Semenya appealed the decision with the Switzerland-based Court of Arbitration for Sport, although today, they decided to uphold the ruling, according to Complex. The Olympian reacted to the decision on Twitter with a shrug emoji and the caption "Sometimes it's better to react with no reaction."
In response to Semenya's request for an appeal, the CAS said: "on the basis of the evidence submitted by the parties, such discrimination is a necessary, reasonable, and proportionate means of achieving the IAAF's aim of preserving the integrity of female athletes in the restricted events."
So far, the CAS and the IAAF have received criticism for their ruling, stating that it unfairly targets athletes like Semenya who were simply born a certain way.