Zurich, July 31 (IANS): Caster Semenya will not be allowed to defend her 800m title at the 2019 World Championships after a Swiss court ruled in favour of an International Association of Athletics Federations ruling that requires her to take a testosterone-reducing medication.

In a statement, Semenya said that she is "disappointed to be kept from defending" her title. "But this will not deter me from continuing my fight for the human rights of all of the female athletes concerned," said the 28-year-old.

The Swiss supreme court had earlier temporarily exempted Caster from an IAAF ruling relating to athletes with differences in sexual development (DSD). However that decision has since been overturned by a tribunal at the same court.

The ruling requires all DSD athletes to reduce their testosterone to below five nmol/L for at least six months if they want to compete internationally at all distances from 400m to a mile. The rule was at the centre of a landmark case at the Court of Arbitration of sport between Semenya and the IAAF. The court found in favour of the federation and ruled that high levels of testosterone does translate into an advantage in women's competition.