Tennis great Martina Navratilova has criticised the Court of Arbitration ruling on Caster Semenya, after her appeal over testosterone levels was dismissed on Wednesday.
The regulations will force athletes with naturally-occurring high levels of testosterone to take medication to lower them, if they want to continue competing.
Semenya, a two-time Olympic 800m champion, and Athletics South Africa had claimed the rules were unlawful, but their appeal has been rejected by the CAS.
Semenya had her case dismissed by CAS
Navratilova, who has been outspoken on the issue of transgender athletes, said on her website:
"The verdict against Semenya is dreadfully unfair to her and wrong in principle.
"She has done nothing wrong and it is awful that she will now have to take drugs to be able to compete.
General rules should not be made from exceptional cases, and the question of transgender athletes remains unresolved."
Over the years opinions and discussions on this matter have been somewhat controversial.
Navratilova continues to be outspoken on the subject.