New research shows trans women have NO athletic advantage over cisgender women

A landmark scientific review published this week has delivered one of the clearest messages yet in the global debate over trans inclusion in sport: trans women do not demonstrate athletic advantages over cisgender women after undergoing gender‑affirming hormone therapy. The findings, drawn from an extensive analysis of existing research, directly challenge widely repeated claims used to justify bans on trans athletes.

The study, led by researchers at the University of São Paulo, reviewed more than fifty studies encompassing data from 6,485 individuals, including nearly 3,000 trans women. This large‑scale review examined a range of metrics, including body composition, strength measures, and cardiovascular fitness before and after hormone treatment.

The researchers found that while transgender women may retain differences in lean body mass compared with cisgender women, these differences do not translate into superior athletic performance. Instead, physical fitness indicators - such as upper‑ and lower‑body strength and maximal oxygen consumption - converge closely with those of cisgender women within one to three years of hormone therapy. These findings counter the longstanding assumption that trans women inherently outperform cis women in sports contexts. 

The evidence also demonstrates that functional performance - the type of performance that determines athletic competitiveness - is comparable across groups despite differences in raw muscle mass or body fat distribution. A review published in the British Journal of Sports Medicine concluded that trans women show no significant differences in upper‑body strength, lower‑body strength, or aerobic capacity when compared with cisgender women following sustained hormone therapy. This holds true even in studies involving thousands of participants, adding weight to the conclusion that physiological changes induced by gender‑affirming care effectively level the playing field. 

Importantly, this new review challenges policy approaches that rely on claims of enduring “male puberty advantage”. While some anatomical traits, such as height or skeletal dimensions, do not change with hormone therapy, the researchers note that the current evidence does not support the idea that these traits provide meaningful or measurable sports‑related benefits to trans women after their physiology has shifted in response to treatment. Contrary to common political rhetoric, the study finds no scientific basis for blanket restrictions that bar trans women from women’s sports on grounds of inherent biological superiority.

These findings arrive at a critical moment. In the UK and elsewhere, sports governing bodies have increasingly adopted exclusionary policies that prohibit transgender women from competing in women’s categories. Many of these policies invoke “fairness” but rely on assumptions that the new research strongly disputes.

For example, last year several UK sports organisations implemented bans after legal rulings affirmed definitions of womanhood tied to biological sex. Yet the São Paulo research team’s conclusions clearly state that their data does not support such broad exclusions, reinforcing the view that policies should be based on evidence rather than social or political pressure.