A review of available literature on transgender female athletes who have taken steps to lower their testosterone concludes that there is no legitimate basis for their banning from elite competition. “Transgender Women Athletes and Elite Sport: A Scientific Review”, commissioned by the Canadian Center for Ethics in Sport (CCES), considered English-language scientific studies with a biomedical or socio-cultural focus, as well as some “grey” studies (non-academic). ) literature published between 2011 and 2021, and focused on the science of testosterone and its effect on athletic performance.
The review authors report that there is no evidence that trans women retain a performance edge after 12 months of testosterone suppression. However, the President and CEO of the CCES Paul Melia highlighted the need for further research while urging that trans female athletes be included and welcomed into elite and high performance women’s sports until evidence shows significant harm or lack of fairness to the other participants.
The review points out that there is almost no research on the performance advantage held by trans female athletes over cisgender women (those whose gender identity is consistent with their birth sex) before and after the HRT (hormone replacement therapy); they are presumed to have an unfair performance advantage based on studies using sedentary cis men or trans women rather than trans female athletes, and therefore the results cannot be used to justify their banning from elite sport .
The report’s first key biomedical finding states that “biological data are extremely limited and often methodologically flawed.” The second says that “Some important studies [on the impact of testosterone suppression] used misleading data sources and actively ignored conflicting evidence. The third states that the available evidence shows that “trans women who have undergone testosterone suppression have no clear biological advantage over cis women in elite sport.”
Current International Olympic Committee guidelines on transgender female athletes, which date from 2015, require that they have reduced their testosterone to no more than 10 nanomoles per liter for at least 12 months before competing in the Olympics; before 2015, they had to have undergone sex reassignment surgery. There have been efforts to tighten the rules ahead of the 2020 Games by scientists who have claimed the current rules are too lenient, but talks have not resulted in a new policy.
The review, which was conducted by E-Alliance, a research center on gender equity in sport led by Dr. Gretchen Kerr from the University of Toronto and Dr. Ann Pegoraro from the University of Guelph, only addressed male-to-female transgender athletes in all sports and cautions that the results may not apply to non-binary or intersex athletes.
The executive summary of the report is available here.