A groundbreaking new study on transgender athletes has found trans women retain a 12% advantage in running tests even after taking hormones for two years to suppress their testosterone. The results, researchers suggest, indicate the current International Olympic Committee guidelines may give trans women an “unfair competitive advantage” over biological women.
World Rugby recently became the first sports federation to ban trans women from women’s rugby, citing “significant” safety risks and fairness concerns. But most sports still follow IOC guidelines from 2015, which permit trans women to play against biological women providing their testosterone remains below 10 nanomoles per litre – a figure higher than average biological female levels, which range from 0.12 to 1.79nmol/L.
However the new study, based on the fitness test results and medical records of 29 trans men and 46 trans women who started gender affirming hormones while in the United States Air Force, appears to challenge the IOC’s scientific position.
The research, published in the British Journal of Sports Medicine, found that before starting their hormone treatment trans women performed 31% more push-ups and 15% more sit-ups in one minute on average than a biological women younger than 30 in the air force – and ran 1.5 miles 21% faster.
Yet after suppressing their testosterone for two years – a year longer than IOC guidelines – they were still 12% faster on average than biological females.
The trans women also retained a 10% advantage in push-ups and a 6% advantage in sit-ups for the first two years after taking hormones, before their advantage disappeared. But the researchers say they “may underestimate the advantage in strength that trans women have over cis women … because trans women will have a higher power output than cis women when performing an equivalent number of push-ups”.
The scientists conclude by saying “more than 12 months of testosterone suppression may be needed to ensure that transgender women do not have an unfair competitive advantage when participating in elite level athletic competition”.
When it initially published its transgender guidelines five years ago, the IOC said its “overriding sporting objective is and remains the guarantee of fair competition”. However, its plans to lower the testosterone limit to 5nmol/L came to nothing because the issue was so contentious. Instead the IOC indicated it wanted sports to implement their own transgender policies.
When asked for its response to the new research the IOC said it was now working on a “a framework for voluntary guidelines on the basis of gender identity and sex characteristics”, adding: “Overall, the discussions to date have confirmed considerable tension between the notions of fairness and inclusion, and the desire and need to protect the women’s category, all of which will need to be reconciled. The IOC aims to release this framework in 2021.”
The academic research also highlighted the benefits of testosterone for trans men. Before taking the hormone, they performed 43% fewer push-ups and ran 1.5 miles 15% slower than their male peers. But after one year there was no longer any difference in push-ups or run time, and the number of sit-ups performed by trans men exceeded the average performance of their male peers.