Caster Semenya says she will "continue to fight for the human rights of female athletes" after losing an appeal against new rules on the levels of testosterone now "allowed" in female middle distance runners.
The double Olympic champion, who won gold in the women's 800m event at the London 2012 and Rio 2016 Games, lost her appeal to Switzerland's Federal Supreme Court on Monday (8 September).
It means that currently South African will be unable to defend her 800m Olympic title in Tokyo next year.
It comes more than two years after World Athletics announced a rule change limiting the levels of testosterone allowed in female athletes competing in events between 400m and a mile.
By no coincidence, these are the the events Semenya, whose naturally high testosterone levels have been a source of contention for years, competes in.
Semenya, 29, was born with "differences of sex development" - sometimes known as being 'intersex'. The new rules would require her to take drugs to suppress her naturally high levels of testosterone.
"I am very disappointed. I refuse to let World Athletics drug me or stop me from being who I am", Semenya said in a statement.
"Excluding female athletes or endangering our health solely because of our natural abilities puts World Athletics on the wrong side of history.
"I will continue to fight for the human rights of female athletes, both on the track and off the track, until we can all run free the way we were born.
"I know what is right and will do all I can to protect basic human rights, for young girls everywhere."
World Athletics issued its own statement in response to the ruling in which the body claimed it "fought for and defended equal rights and opportunities for all women and girls."
Not, it seems, those women and girls whose differences in sex development mean they are considered 'other' in the sport.
"We therefore welcome today's decision by the Swiss Federal Tribunal to uphold our DSD regulations as a legitimate and proportionate means of protecting the right of all female athletes to participate in our sport on fair and meaningful terms", the statement read.
The Swiss Supreme Court said: "Fairness in sport is a legitimate concern and forms a central principle of sporting competition. It is one of the pillars on which competition is based."