A controversial new study from Brazilian researchers asserts that transgender women do not hold any inherent physical edge over biological females in athletic competition.
The research, conducted by scientists at the University of Sao Paolo and published in the British Journal of Sports Medicine, examined strength, fitness levels and body composition among transgender individuals receiving hormone therapy compared with cisgender people.
Drawing on 52 separate studies encompassing more than 5,000 transgender participants and over 1,000 women aged 14 to 41, the analysis found that while trans women retained greater lean mass after hormonal treatment, their overall physical fitness was “comparable” to other women.
The researchers concluded their findings “does not justify blanket bans” on transgender women participating in female sport.
The study has drawn sharp criticism from academics who argue it suffers from significant methodological shortcomings.
Professor Alun Williams, who specialises in sport and exercise genomics at Manchester Metropolitan University, contends that the research failed to monitor fitness levels over time or before hormone treatment commenced.
He argues it is “almost worthless to compare groups without tight assessment of training history”.
A controversial new study from Brazilian researchers asserts that transgender women do not hold any inherent physical edge over biological females in athletic competition
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PA
Professor Williams also highlighted that hormonal intervention following puberty cannot alter skeletal structure, including height, limb length and shoulder width.
“Those advantages to men in many sports remain in transgender women regardless of hormone changes,” he said.
He added: “I don’t agree with the authors that the studies published to date, or their review of them, overturn the evidence for inherent athletic advantage in transgender women.”
Noa-Lynn van Leuven is a transgender darts player
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PAThe Brazilian study’s conclusions stand in stark contrast to earlier research in this field.
A 2022 study demonstrated that male-to-female transitioners remained faster, stronger and more physically capable than most women even after undergoing hormone treatment.
The authors of the new research acknowledge their evidence was of mixed quality and lacked diversity in terms of age groups, sporting disciplines and competitive levels.
They also concede that most studies included in their analysis did not feature elite-level athletes.
“Although the current data do not justify blanket bans, critical gaps in literature were found, notably the underrepresentation of transgender athletes who may retain more ‘muscle memory’,” the researchers wrote.
The study has been criticised by both academics and sex-based rights organisations for flaws in its methodology.
Following last year’s Supreme Court ruling that the legal definition of a woman under the Equality Act is based on biological sex, numerous UK sporting bodies prohibited transgender women from competing in female categories, including cricket and football.
Fiona McAnena, director of campaigns at Sex Matters, dismissed the study’s conclusions.
“Men do not shrink or magically lose all their male advantages when they identify as women, no matter what hormones they take,” she said.
Dr Blair Hamilton, a research associate at Manchester Metropolitan University, offered a more measured response, stating the findings were “consistent with what we’ve seen in the wider scientific literature”.
However, Dr Hamilton cautioned that understanding the impact on elite competition requires studying elite athletes, noting “there are very few openly transgender elite athletes anywhere in the world”.

