Transgender women in sport: Does ‘comparable’ mean ‘equal’?

A recent systematic review in the British Journal of Sports Medicine claiming "comparable" physical fitness between transgender and cisgender women faces significant scrutiny regarding its methodology and data quality. While the study suggests hormone therapy reduces testosterone and muscle mass enough to bridge the performance gap, critics like sports scientist Professor Alun Williams argue the underlying evidence is too poor to support such definitive conclusions. A primary concern involves "cross-sectional" studies that fail to control for training intensity; for instance, one included study compared transgender volleyball players training four hours a week against cisgender women training fourteen hours at a higher competitive level. Although lead author Bruna Guarlano maintains that "comparable" simply denotes a lack of statistically significant differences rather than total equivalence, the lack of robust longitudinal data leaves the question of retained male biological advantage in sports largely unresolved.