World Athletics will introduce mandatory testing for anyone entering female competitions to verify their biological sex, insisting they are necessary to protect women's sport.
It is the latest move overseen by Sebastian Coe - as president of the governing body - to address the gender eligibility issue, two years after banning anyone assigned male at birth from female events.
Lord Coe said after a World Athletics Council meeting today that they could adopt non-invasive cheek swab tests or dry blood tests that only have to be carried out once on an athlete.
"This we feel is a really important way of providing confidence and maintaining that absolute focus on the integrity of competition," he said.
The tests would seek to verify if someone has transitioned to a female after going through male puberty or if they had differences of sex development that provided testosterone advantages.
The tests would seek to verify if someone has transitioned to a female after going through male puberty or if they had differences of sex development that provided testosterone advantages.
Testing providers are now being sought.
Lord Coe said: "The pre-clearance testing will be for athletes to be able to compete in the female category.
"The process is very straightforward frankly, very clear and it's an important one and we will work on the timelines.
"Neither of these are invasive. They are necessary and they will be done to absolute medical standards."
It follows US President Donald Trump ahead of the 2028 Los Angeles Olympics saying there are only two sexes - male and female - while calling on sports to ban transgender women from women's events.
The International Olympic Committee has previously called a return to sex testing a "bad idea", but incoming IOC President Kirsty Coventry is not ruling it out, having also talked about protecting the female category.
"This is a conversation that's happened and the international federations have taken a far greater lead in this conversation," she told Sky News after her election last week.
"What I was proposing is to bring a group together with the international federations and really understand each sport is slightly different.
"We know in equestrian, sex is really not an issue, but in other sports it is.
"So what I'd like to do again is bring the international federations together and sit down and try and come up with a collective way forward for all of us to move."
Reem Alsalem, the UN's special rapporteur on violence against women and girls, last year called on the IOC to reintroduce sex testing or female athletes to protect them from injuries amid concerns about eligibility.
The IOC introduced "certificates of femininity" at the 1968 Mexico Games. But those chromosome-based tests were deemed unscientific and unethical and dropped ahead of Sydney 2000.
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