We often see claims in media that transgender women, people assigned male at birth who socially and medically transition to female, have an inherent and unfair athletic advantage over cisgender women. However, a new meta-analysis published in the British Journal of Sports Medicine comparing physical fitness and body composition of transgender and cisgender individuals suggests otherwise.
The meta-analysis looked at fifty-two studies with 6,484 total participants. The researchers specifically looked at studies where the body composition of transgender individuals was compared to either their own body composition/physical fitness before and after gender-affirming hormone therapy (GAHT) or versus cisgender controls. Transgender women had similar relative fat mass, relative lean mass, upper-body strength, lower-body strength, and maximal oxygen consumption in comparison to cisgender women. This information was gathered by comparing the average difference in each metric (i.e. muscle mass) between that of cisgender and transgender women.
It must be noted, however, that these findings were all either rated low or very low on the GRADE scale. The GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) is a method of assessing the certainty in evidence and the strength of recommendations in health care. Despite this low certainty, these findings fall in line with the outcomes from similar studies.
In April 2024, a study financed by the International Olympic Committee found that transgender female athletes showed higher grip strength, but lower jumping ability, lung function, and relative cardiovascular fitness than cisgender women. The study’s authors emphasized the study’s small sample size, but nevertheless pointed out one of its most important findings: Trans women are not biological men.
These studies continue to muddy the purported justifications for blanket bans on transgender women competing in women’s sports. Many of the existing studies are admittedly more suggestive than probative in that they lack a large sample size and don’t follow athletes through their transitions. Yet still, these studies emphasize that broad bans on transgender women competing in women’s sports have not been proven necessary based on science.
Additionally, the need for these rules and prohibitions may also be proven unnecessary based on the sheer number of transgender athletes actually competing at a high level. In late 2024, NCAA President Charlie Baker testified that out of more than 500,000 total NCAA athletes, he believed less than ten of them are transgender. Not 10%, but ten individuals. That is 0.002% of all NCAA athletes across all three divisions.
In January, the United States Supreme Court heard oral arguments in Little v. Hecox and West Virginia v. B.P.J., a case regarding state laws in Idaho and West Virginia that ban transgender women and girls from competing on girls and women’s sports teams. In February 2025, President Trump signed Executive Order 14201, “Keeping Men Out of Women’s Sports,” which was written to prohibit trans women from playing women’s sports across all education levels. As more studies are conducted and more research is published, it will be interesting to see whether lawmakers will be more persuaded by science or their own beliefs.
Sources:
https://bjsm.bmj.com/content/early/2026/01/22/bjsports-2025-110239
https://www.nytimes.com/2024/04/23/world/europe/paris-olympics-transgender-athletes.html
https://www.pbs.org/newshour/show/what-science-tells-us-about-transgender-athletes
Photo source: https://www.stonewallfoundation.org/impactapril2021/2021/4/6/fighting-trans-discrimination
Mary Starr is a 3L at the University at Buffalo School of Law with a concentration is sports law. In law school, she has served as the president of Phi Alpha Delta, event coordinator for OutLaw, event coordinator for the Jewish Law Students Association, a senior associate on the Buffalo Human Rights Law Review, a Student Director with the Peer-to-Peer Mentorship Program, and she is a student ambassador. Outside of school, Mary can be found playing hockey, rock climbing, or explaining how she ended up being raised a Bruins fan (despite being raised in Rochester, NY!).
Leave a Reply