Athletics' global governing body has disclosed that up to 60 competitors who underwent male puberty have reached finals in women's track and field competitions at major championships over the past quarter-century.
The revelation emerged during a scientific conference in Tokyo on Friday, where officials defended new biological screening measures for the upcoming world championships.
Senior representatives from World Athletics presented evidence spanning from 2000 to the present, documenting instances where athletes with differences of sex development competed in female categories at continental and global events.
The findings have reignited debate about fairness and biological advantages in women's sport.
Caster Semenya has refused to take medication to lower her natural testosterone levels | PAThe sport's governing body has implemented cheek swab testing to identify the SRY gene, which determines biological sex, ahead of the Tokyo world championships.
Dr Stephane Bermon, who leads health and science at World Athletics, delivered findings from a quarter-century of research to a scientific panel in the Japanese capital.
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His presentation outlined why the organisation considers such screening essential, arguing that athletes with 46 XY karyotypes and male testes, though recorded as female at birth, have "compromised the integrity of the female competitions".
"Everyone is watching World Athletics and we are leading in this area," Bermon told the assembled experts.
The data revealed that athletes with differences of sex development appear in elite finals at a rate 151.9 times higher than their prevalence in the general population would suggest.
Bermon disclosed there were "approximately 50-60 cases of DSD (differences of sex development) in athletics", with these individuals accounting for 135 finalist positions across international competitions between 2000 and 2023.
Namibia’s Christine Mboma has not competed since sex testing rules were implementedq
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The statistics were compiled through anti-doping protocols that detected elevated testosterone levels, though this methodology potentially underestimates the true figure.
The scale of over-representation has surprised many within athletics, significantly exceeding previous estimates from sporting authorities and researchers.
Several prominent athletes with DSD conditions have achieved notable success, including South Africa's Caster Semenya, who secured Olympic gold in the 800m at both the 2012 and 2016 Games.
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Christine Mboma of Namibia claimed silver in the 200m at Tokyo 2020, generating substantial media attention.
Both have ceased competing at elite level following the introduction of testosterone suppression requirements.
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South Africa's Caster Semenya secured Olympic gold in the 800m at both the 2012 and 2016 Gamesq
|PA
Sebastian Coe, World Athletics president, emphasised that "gender cannot trump biology" whilst defending the new measures.
However, Andrew Sinclair, the professor who identified the SRY gene, criticised the testing approach as "overly simplistic" and not "cut and dried".