Custer Seeds of South Africa still hopes to win a third gold medal at the 800 meters at the 2020 Tokyo Olympics, but it will not meet this year's World Athletics Championships after the latest legal decision in a continuing, high-profile a case for testosterone levels and restrictions on intersex athletes competing in certain women's events.
A Swiss court overturned a decision in June that allowed the 28-year-old Seed to conduct its signature race earlier this summer.
"I am very disappointed that I cannot defend my title," Seed said on Tuesday, "but that will not stop me from continuing to fight for the human rights of all women athletes concerned."
The governing body of Track, the International Association of Athletics Federations, seeks to limit testosterone levels in some athletes in certain events, claiming that those with higher testosterone receive an unfair advantage. Semenya will be allowed to continue racing if her levels go down through hormone therapy, but she refuses to undergo it.
I.A.A.F. said his rule applies to athletes who have the X and Y chromosomes, the standard male model and therefore testosterone in the male range.
In May I.A.A.F. has won support for its position in the Court of Arbitration for Sport. The court said limiting testosterone limits was discriminatory but necessary to achieve equality for women. That decision was overturned by a Swiss court in June.
The last decision of the Swiss Federal Tribunal overturns this again. This prevents Semenya from racing from 400 meters to one mile, including her preferred distance of 800 meters. I.A.A.F. said she could run longer or shorter races.
Semenya always defined as a woman. She has won 800 meters in the last two Olympic Games and has three world titles in the event, including her last run in 2017.
She was in good shape this year too, winning the Diamond League in Doha, Qatar, May and Stanford , California, in June.
The Doha World Championships are scheduled to begin in late September.
This is an evolving story and will be updated.