The South African middle distance runner attempted to cancel the IAAF’s ruling that requires athletes with naturally high testosterone levels to medically reduce them to be approved for international competitions.

In a statement on Wednesday, CAS said: “By majority, the CAS panel has dismissed the requests for arbitration, considering that the claimants were unable to establish that the DSD [differences of sex development] regulations were ‘invalid’.

“The panel found that the DSD regulations are discriminatory, but the majority of the panel found that, 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 athletics in the restricted events.”

CAS said, however, that the panel “expressed some serious concerns as to the future practical application” of the DSD regulations.

Two-time Olympic 800m winner Semenya found the testosterone ruling discriminative, as it didn’t cover all athletics disciplines, extending to just middle distances (from 400metres to 1,500m), dominated by Semenya.

The ruling, which should have come into effect last November, required any female athlete, including those with DSD, to have a testosterone level below 5 nmol/L.

The IAAF’s decision to prohibit women with high testosterone levels from competing was based on scientific research that shows higher levels give athletes a significant advantage over competitors.

Semenya responded to the news on social media with a shrugging emoj and the message: “Sometimes it’s better to react with no reaction.”