Sex Eligibility Screening in Women's Sport: When Does the Pursuit of Integrity Become a Human Rights Violation?
From new world records to groundbreaking policy changes, the 2025 World Athletics Championships will be remembered for setting precedents that stretch beyond the track and field.
On 1 September, new regulations limiting participation in female categories to “biological females” entered into force.[1] This meant that for the first time athletes wishing to compete in the Championships, which kicked off on 13 September, had to undergo testing for the SRY gene (a marker predominantly found on the male Y chromosome) to prove their biological eligibility.[2]
This policy change came in response to recommendations made by the Working Group on Gender Diverse Athletes established by World Athletics Council, which advocated for the revision of the eligibility rules to bar athletes who were born with certain differences of sexual development (“DSD”) from competing in the female category.[3] These regulations were intended to merge previous World Athletics eligibility regulations for transgender and DSD athletes together, replacing the previous rules that allowed athletes to compete in the female division if they underwent testosterone suppression treatment.
Who will be affected by the rule change?
The percentage of people born with DSD is debated and remains unclear. However, in its report on the human rights of LGBTI people, the United Nations Office of the High Commissioner for Human Rights estimates that approximately 1.7% of the world’s population is intersex.[4]
DSD is a general term used to describe a range of biological conditions in which a person has both male and female sex characteristics. These regulations specifically aim to bar athletes whose DSD is characterised by the presence of XY chromosomes alongside female sex characteristics, leading them to identify as female with very limited exceptions.[5]
According to Stéphane Bermon, head of health and science at World Athletics, athletes with DSD are overrepresented in elite competition with 50-60 athletes with DSD competing in at least one elite final over the last 25 years.[6] However, it is important to note that while these figures are based on anti-doping tests that found high testosterone levels in participants, it does not necessarily mean that these athletes had a DSD of the kind that would rule them ineligible to compete in the female division under World Athletics’ new rules.
History of Eligibility Verification in Women’s Sport
Regulations governing female eligibility in elite sport have a long and invasive history. These began with universal mandatory physical and gynaecological examinations in the 1960s, and evolved into biological testing, used until the 1990s, which involved mandatory sampling to identify chromosomal karyotypes and specific genes.[7] By the 2000 Olympics, the universal testing had been phased out by both the International Association of Athletics Federations (“IAAF”), now World Athletics, and the International Olympic Committee (“IOC”), due to concerns surrounding accuracy and the overall benefit of such a regime. This led to the implementation of a “suspicion-driven” model which tested female athletes who had been identified as “masculine”.[8] This policy was most notably thrust into the public eye through experiences of two-time 800m Olympic champion Caster Semenya.
In 2009, 18-year-old Caster Semenya won gold at the World Athletics Championships in Berlin. Following her victory, she faced intense scrutiny from both the public and World Athletics, with details of her medical testing, body and gender identity widely discussed in the media, and, in some cases, by World Athletics officials themselves.[9] The events, which she described as ‘the most profound and humiliating experience of [her] life’,[10] were followed by the 2011 introduction of new regulations governing the eligibility of females with hyperandrogenism in the World Athletics women’s category. Under the new regulation, to be eligible to compete, women with hyperandrogenism, defined as the excessive production of androgens or testosterone, were required to take medication or undergo certain procedures to artificially lower their testosterone levels.[11]
In 2015, following a legal challenge by Indian sprinter Dutee Chand, the Court of Arbitration for Sport (“CAS”) found that World Athletics had not provided sufficient evidence to establish a clear link between elevated testosterone levels and enhanced athletic performance in hyperandrogenic athletes. This led to a suspension of hyperandrogenism regulations for two years to allow World Athletics time to conduct further research on their proposed regulations.[12]
CAS Ruling in Semenya v World Athletics
After the two-year suspension period, World Athletics introduced the DSD Regulations in 2018. Under these regulations an athlete had to:[13]
1. Be legally recognised as either female or intersex;
2. Reduce her blood testosterone levels to below 5 nanomoles per litre (nmol/L) for a continuous period of at least six months; and
3. Maintain those testosterone levels below 5 nmol/L continuously thereafter.
Semenya challenged these regulations before CAS, arguing that they were discriminatory on multiple grounds. She contended that the rules discriminated on the basis of sex, as only female athletes were subjected to the testing; on the basis of physical appearance, as testing was triggered by subjective assessments of ‘masculine’ features; and on the basis of biological traits by targeting athletes for natural, genetic characteristics beyond their control. She also argued that the regulations were unnecessary and unsupported by sufficient scientific evidence. This led to arbitrary thresholds for "acceptable" testosterone levels and selective application to athletes competing in certain restricted events (notably they applied to all events that Semenya herself competed in). In her submissions, she asserted that DSD traits should be recognised as just another form of genetic advantage common in elite sport. She also emphasised that the regulations inflicted significant physical, emotional, and professional harm, forcing affected athletes to choose between undergoing medically unnecessary intervention and their athletic careers.[14]
The CAS panel unanimously agreed with Semenya and found the DSD regulations to be discriminatory. Critically, however, the majority also found this discrimination to be a “necessary, reasonable and proportionate means” of upholding the integrity of female athletics and the "protected class" of female athletes in certain events.[15]
They acknowledged the difficulty faced by sporting organisations in enforcing a binary sex classification, given that modern understandings of biology no longer align with traditional definitions. The panel accepted World Athletics’ evidence that testosterone is the primary driver of sex-based performance differences and as such, they reasoned eligibility criteria for the female category must align with the biological reasons for its existence. The panel therefore concluded that regulating participation based on testosterone levels, as World Athletics proposed, was a justifiable and proportionate response to ensure fair competition in the protected female category and upheld the DSD regulations.[16]
ECtHR Ruling in Semenya v Switzerland
Semenya appealed this decision to the Swiss Federal Supreme Court who upheld CAS’s rulings. This gave rise to a human rights challenge before the European Court of Human Rights (“ECtHR”), which delivered its final ruling on the case on 10 July 2025.
Semenya submitted that the Swiss Federal Supreme Court’s ruling on the CAS award had failed to uphold her rights under the European Convention on Human Rights (“ECHR”), particularly her right to a fair trial under Article 6, her right to have her private life respected and the prohibition of discrimination under Articles 8 and 14 respectively, as well as her right to an effective remedy under Article 13.[17]
Ultimately, the ECtHR found that Semenya’s right to a fair trial had been infringed by the Swiss Court, finding that they had not adequately scrutinised CAS’s decision as required by Article 6.[18] They highlighted the Swiss Court’s refusal to engage with concerns raised by Semenya surrounding the “outing” of female athletes with DSD and the compatibility of DSD Regulations with fundamental human rights.[19]
They, however, dismissed her claims under Articles 8, 13 and 14, finding that, as a South African citizen, she did not fall within Swiss jurisdiction under Article 1 of the ECHR.[20] This meant that they did not need to address the question of whether the DSD regulations and others like them were ‘necessary, reasonable and proportionate means’ of discrimination or if they were, in truth, violations of Semenya’s human rights.
Critically, this ruling on jurisdiction was criticised by four of the fifteen sitting judges of the ECtHR. They cautioned that this type of ruling would create a legal loophole for European private bodies like World Athletics to avoid substantive human rights oversight and effectively deny affected individuals like Semenya a path to legal remedy.
The New Regulations: Human Rights Issues and Future Legal Challenges
In its 2025 consultation report, World Athletics claims that new research demonstrates that testosterone suppression treatment alone does not sufficiently address the performance gap between female athletes with DSD and those without. [21] As a result, it argues that regulations that enforce a strict binary division of competition categories based on chromosomal sex are necessary.
In its 2019 arbitration on the DSD regulations, CAS agreed with World Athletics that the classification of athletes as male and female was a challenging but fundamental requirement of maintaining the binary structure of its competition categories. Whether the lines upon which they do so are adequately “necessary, reasonable and proportionate” to ensure the integral structure of these divisions is a matter that may be taken into question.
These new regulations address one of the ethical and human rights dilemmas posed by the earlier rules, which essentially left female athletes with DSD no choice but to take testosterone suppressing medication to lower their levels to an arbitrarily defined threshold. Yet it does so by entirely removing the option of elite competition for athletes who by no fault of their own have been born with DSD. Per the United Nations, these regulations still violate athletes’ right to non-discrimination, as they are denied the right to work as elite athletes, subjected to undue scrutiny and privacy violations, and denied the right of bodily autonomy simply because they have been born with differences in sex characteristics.[22]
Given the ECtHR findings on the jurisdictional challenges of appealing CAS decisions on human rights grounds, this is a legal challenge that will likely be settled within the confines of CAS itself. The outcome will be determined by their evaluation of whether, in the pursuit of preserving the integrity of female competition, it is “necessary, reasonable and proportionate” to exclude an entire class of female athletes from competing at an elite level.
Conclusion
World Athletics President, Sebastian Coe, has stated that attracting more women to elite and amateur sport alike depends on their belief that there is “no biological glass ceiling”.[23] Yet the regulations restricting, and now outright banning, women with certain DSD characteristics from competing at an elite level appear to impose precisely this kind of barrier Coe claims to reject. In enforcing such restrictions, World Athletics risks undermining the very integrity that it seeks to protect. Within a legal framework where judicial oversight has been greatly limited, this contributes to the development of a dangerous precedent that normalises human rights infringements in women’s sport.
References:
[1] World Athletics, Regulations for the Implementation of Eligibility Rule 3.5 (Male and Female Categories) (Approved by Council 23 July 2025, effective 1 September 2025) [3.2].
[2] World Athletics, ‘World Athletics introduces SRY gene test for athletes wishing to compete in the female category’ (Press Release, 31 July 2025) https://worldathletics.org/news/press-releases/sry-gene-test-athletes-female-category.
[3] World Athletics, Recommendations to the Eligibility Conditions for the Female Category (Consultation Document, 5 March 2025) [1] (‘World Athletics Recommendations’).
[4]United Nations Office of the High Commissioner for Human Rights, 'Intersex People' (Fact Sheet No. 24, 2015) https://www.ohchr.org/en/sexual-orientation-and-gender-identity/intersex-people.
[5] Robert Resta, ‘Why SRY? World Athletics Decides Who Is Female’ (Web Article, 3 September 2025) https://thednaexchange.com/2025/09/03/why-sry-world-athletics-decides-who-is-female/.
[6] Sean Ingle, 'Sex Tests Brought in After Data Showed 50–60 DSD Athletes in Finals, World Athletics Says' The Guardian (online, 19 September 2025) https://www.theguardian.com/sport/2025/sep/19/sex-tests-brought-in-after-data-showed-50-60-dsd-athletes-in-finals-world-athletics-says.
[7] Vanessa Heggie, 'Testing Sex and Gender in Sports: Reinventing, Reimagining and Reconstructing Histories' (2010) 34 Endeavour 157, 159 https://doi.org/10.1016/j.endeavour.2010.09.005.
[8] United Nations High Commissioner for Human Rights, Intersection of Race and Gender Discrimination in Sport: Report of the United Nations High Commissioner for Human Rights, UN Doc A/HRC/44/26 (15 June 2020) (‘Intersection of Race and Gender Discrimination in Sport’).
[9] Mokgadi Caster Semenya v International Association of Athletics Federations and Athletics South Africa v International Association of Athletics Federations (Arbitral Award, Court of Arbitration for Sport, Cases no 2018/O/5794 and no 2018/O/5798, 30 April 2019) [75] (‘Semenya CAS Award’).
[10] Ibid. [74].
[11] World Athletics, 'IAAF to introduce eligibility rules for females with hyperandrogenism' (Press Release, 14 April 2011) https://worldathletics.org/news/iaaf-news/iaaf-to-introduce-eligibility-rules-for-femal-1.
[12] Court of Arbitration for Sport, CAS Suspends the IAAF Hyperandrogenism Regulations Until End of September 2017 (Media Release, 28 July 2017) https://www.tas-cas.org.
[13] DSD Regulation 2.3.
[14] Semenya CAS Award (no 9) [50]–[72].
[15] Ibid. [626].
[16] Ibid. [557].
[17] Semenya v Switzerland (European Court of Human Rights, Grand Chamber, Application No 10934/21, 10 July 2025) [1].
[18] Ibid. [133].
[19] Jasper Wauters and Nikolas Hertel, ‘European Court of Human Rights Delivers Final Ruling in the Case of Semenya v Switzerland’* (White & Case LLP, 18 July 2025) https://www.whitecase.com/insight-alert/european-court-human-rights-delivers-final-ruling-case-semenya-v-switzerland.
[20] Semenya v Switzerland (no 17) [151-152].
[21] World Athletics Recommendations (n3).
[22] Intersection of Race and Gender Discrimination in Sport (n8) [34].
[23] Ingle (n6).