Transgender women athletes have no advantage over cisgender women, a study in the British Journal of Sports Medicine has found. The researchers found that there was no evidence “to justify blanket bans” on trans women competing in women’s sport and that the data doesn’t support “inherent athletic advantage theories”. The pooled data analysis of 52 studies on 6,485 people considered strength, fitness and body composition of trans women receiving gender-affirming hormone therapy. Trans women were found to have more lean mass (a proxy for muscle), but there were no observable differences in upper or lower body strength, or in a key measure of cardiorespiratory fitness – maximal oxygen consumption – between trans and cis women. The researchers said: “Although the current data do not justify blanket bans, critical gaps in literature were found, notably the under-representation of transgender athletes who may retain more ‘muscle memory’.” They added that more long-term and high-quality studies are needed to “prioritise performance-specific metrics in transgender athletes” but the “scarce number” of trans people in elite sport makes this difficult. The inclusion of trans women in women’s sports has been a key issue for anti-trans campaigners. Last year, the Football Association banned trans women from taking part in women’s football in England, and the England and Wales Cricket Board banned trans women from all levels of women’s cricket. This came after the UK supreme court ruled in April 2025 that the legal definition of a woman under the Equality Act is based on biological sex.