Gene tests begin in women’s athletics – new rule explained

This week, new regulations will require all female athletes competing in the female category of world rankings to perform a one-time gene test.

World Athletics says the sex screening – which detects the presence of a Y chromosome – is to protect the integrity of women’s competition.

The Y chromosome’s SRY gene, or “sex-determining region Y gene,” is a component of the test that reveals male characteristics.

If a human embryo has XY chromosomes the SRY gene leads to the formation of testes, which then produce hormones including testosterone that lead to male development – and can increase muscle mass and strength.

With XX chromosomes and no SRY gene, male athletes who were born male and went through male puberty have a higher level of physiological advantage than female athletes.

It is a cheek swab or blood test, which is done once in an athlete’s life by each national federation. The athlete is eligible to compete in the female category if the Y chromosome test results in negative results, i.e., it is absent.

However, according to World Athletics, “these individuals with typically male chromosomes may have atypical development of reproductive or sexual anatomy due to variations in the SRY gene or other related genetic factors,” with some having a female gender at birth, and that a positive test may occur if the athlete has the DSD condition 46 XY.

In such cases, unless the athlete has complete androgen insensitivity syndrome (CAIS) – and has not gone through male puberty – they would be ineligible to compete in the female category.

World Athletics says more than 90% of the athletes due to take part in the World Championships later this month have been tested, with any outstanding cases to be conducted in Tokyo.

Due to the outlawing of genetic testing for non-medical reasons in some nations, such as France and Norway, forcing some athletes to give samples abroad, Lord Coe, its president, has acknowledged the time frame has been “tight” and there has been “added complexity.”

Since South African Caster Semenya won the 800-meter final at the World Championships in 2009, gender has been a big deal in sport, with the latter continuing to dominate at the distance.

She was born with a 5-alpha-reductase deficiency of 46 XY 5-ARD. People with this particular DSD have male XY chromosomes, but some are recorded as female at birth.

All three women’s 800-meter runners-up at the 2016 Olympics in Rio were DSD athletes, which heightened calls for tighter regulations. World Athletics then insisted that for track events from 400m up to the mile, DSD athletes must reduce their testosterone levels in order to be eligible.

Semenya objected, contending that it violated and discriminated against her.

World Athletics’ rules became stricter in 2023 after a lengthy legal battle. Transgender women who had gone through male puberty were banned from competing in women’s events, while DSD athletes had to further reduce their testosterone levels and for longer, and in all track and field events.

Then, earlier this year, a Working Group for World Athletics urged pushing the envelope, arguing that recent research showed that testosterone suppression could only partially reduce the male advantage overall.

The SRY gene is “a reliable proxy for determining biological sex,” according to the governing body, and the majority of those polled were in favor of a cheek swab test.

“It is really important in a sport that is permanently trying to attract more women that they enter a sport believing there is no biological glass ceiling”, said Lord Coe at the time.

World Boxing also introduced mandatory sex testing this year, with any fighters wanting to take part in the female competition at the World Championships in Liverpool this week having had to take a test.

The governing body declared in May that athletes who are deemed to be male at birth will be eligible to compete in the male category based on the presence of Y chromosome genetic material (the SRY gene) or a difference in sexual development (DSD) where male androgenization occurs.

Imane Khelif and Lin Yu-ting both won gold at the 2024 Paris Olympics despite being exempt from the previous year’s World Championships for allegedly failing gender eligibility tests conducted by the then-governing body, the IBA, which was the source of much controversy.

In order to avoid stigmatizing or discriminating against athletes, the IOC has been cautious about sex screening. The distinction between men and women is made clear by XX or XY, according to former president Thomas Bach in 2024. This is scientifically not true any more”.

However, the UN’s special rapporteur on violence against women demanded that sex screening be reinstated following the Paris 2024 boxing controversy. According to a group of 32 academics, targeted testing was “overwhelmingly preferable” based on allegations, suspicion, and bias, according to a group of experts.

New IOC president Kirsty Coventry says protecting the female category is a priority, and seems open to applying such a test across all sports. US President Donald Trump has stated that any form of sex testing will be used in the 2028 women’s competition at the LA Olympics.

Before the requirement for chromosome-based cheek swab tests, the IOC used visual inspections in the 1960s, but there were concerns that they were invasive and degrading.

However, there were issues. Spanish hurdler Maria Jose Martinez Patino was barred from competition in 1986 after failing the test, but later examinations showed that while she had XY chromosomes she also had CAIS – meaning her body never gained benefits from the increased testosterone created by her internal testes.

Gender verification tests were abolished in the 1990s amid a number of “false positives” and concerns that female athletes were being punished for natural variations. She was reinstated.

According to Lord Coe, athletes have “overwhelmingly supported” the new tests. Sex Matters, a campaign group, called for the screening to be resumed and said that “every sport needs to follow the example of World Athletics and World Boxing.”

However, US runner Nikki Hiltz – who is transgender and non-binary – said the gene testing was “disappointing”, adding: “I just don’t like the precedent that it sets”.

He claimed that the science does not support this overly simplistic claim and that using SRY to establish biological sex is wrong. Additionally, he raised concerns about the possibility of a false positive and accidental contamination.

And Madeleine Pape, a former Australian Olympian and a sociologist at the University of Lausanne, has also raised concerns about the test inadvertently ‘ outing ‘ athletes – some of whom may never have known they had a DSD.

She claimed that while it is far from being scientifically accurate as a performance indicator, it is also extremely harmful to the athletes involved.

Any initial positive results, according to World Athletics, will be followed up by further medical evaluations, ensuring an accurate diagnosis before an eligibility determination is made. It says a healthcare specialist will also discuss the results with an athlete, helping them understand any medical, psychological or social implications.

Athletes have been informed that they will upload their test results to a secure, encrypted platform and that they can appeal their results via the Court of Arbitration for Sport (CAS).

Although some experts predict legal challenges, Lord Coe claims he is confident that the policy will uphold any demands made by international human rights organizations.

Semenya has been fighting for years in court against the outdated sex eligibility laws. In 2019 she unsuccessfully challenged them at CAS. However, when she lost a further appeal in 2020, the European Court of Human Rights determined that her right to a fair hearing was violated by the Swiss Federal Supreme Court in July.