Transgender women athletes Photo: 123RF
World Athletics has banned transgender women from competing in elite female competitions if they have gone through male puberty, the sport's governing body said.
World Athletics has banned transgender female athletes from competing in the female category at international events.
The governing body's president, Lord Coe, said no female transgender athlete who had gone through male puberty would be permitted to compete in female world ranking competitions from 31 March.
A working group will be set up to conduct further research into the transgender eligibility guidelines.
"We're not saying no forever," he said.
Under previous rules, World Athletics required transgender female athletes to reduce their amount of blood testosterone to a maximum of 5nmol/L, and stay under this threshold continuously for a period of 12 months before competition.
Lord Coe added the decision was "guided by the overarching principle which is to protect the female category".
He noted there were currently no transgender athletes competing internationally in the sport.
The council also voted to tighten restrictions on athletes with Differences in Sex Development (DSD) cutting the maximum amount of plasma testosterone for athletes in half, to 2.5 nanomoles per litre from five.
The tighter rules will impact DSD athletes such as two-times Olympic 800 metre champion Caster Semenya, Christine Mboma, the 2020 Olympic silver medallist in the 200m, and Francine Niyonsaba, who finished runner-up to Semenya in the 800 at the 2016 Olympics.
Swimming's world governing body World Aquatics voted last June to bar transgender women from elite competition if they had experienced any part of male puberty. A scientific panel had found that even after reducing their testosterone levels through medication, transgender women still had a significant advantage.
The vote passed with 71 percent of the national federations in favour.
World Athletics regulations around DSD previously required women competing in events between 400 metres and a mile to maintain testosterone levels below five nanomoles per litre.
At the 2020 Olympics, South Africa's Semenya and Burundi's Niyonsaba were both barred from the 800m before turning their attention to the 5,000.
Semenya failed to qualify for the Games while Niyonsaba made the final before being disqualified for a lane violation.
Namibia's Mboma, prevented from running the 400m, switched to the 200m, winning silver.
DSD athletes have male testes but do not produce enough of the hormone Dihydrotestosterone (DHT) that is necessary for the formation of male external genitalia.
-BBC / Reuters