Is Transgender Athlete Inclusion Destroying Women's Sports?

World Aquatics, the international governing body for swimming, voted in June 2022 to restrict transgender athletes from competing in elite women's events if they have undergone any part of male puberty. The policy, which was developed by a transgender task force including athletes, scientists, and medical experts, requires transgender swimmers to have completed their transition before age 12 and to maintain testosterone levels below a specified threshold. The decision came after Lia Thomas became the first transgender woman to win an NCAA Division I national championship in the 500-yard freestyle. The policy was framed by the organization as a way to protect fairness and competitive integrity in women's swimming, citing scientific evidence of performance advantages retained by biological males even after testosterone suppression.

A 2023 systematic review published in the British Journal of Sports Medicine examined studies on physical performance in transgender athletes. The review found that biological males who undergo testosterone suppression for at least 12 months show significant reductions in muscle mass, strength, and hemoglobin levels, but that performance advantages in sports like swimming, cycling, and running may still persist, particularly in events emphasizing upper-body strength and power. The review noted that the magnitude of residual advantage varies by sport and event, and that current data are limited by small sample sizes and short follow-up periods. The authors concluded that while hormone therapy narrows the gap, it does not fully eliminate differences in certain athletic domains, supporting the rationale for sport-specific eligibility policies.

A 2023 study published in the journal Sports Medicine followed transgender women athletes over a 12-month period of testosterone suppression and compared their performance metrics with cisgender female athletes. The study found that after one year of hormone therapy, transgender women showed no statistically significant advantage in running performance (5K and 10K times) and showed comparable endurance and cardiovascular capacity to cisgender women. The researchers emphasized that previous claims of universal advantage were based on data from untrained or partially transitioned individuals, and that long-term hormone therapy substantially reduces muscle mass, bone density, and aerobic capacity. The study was welcomed by trans-inclusion advocates as evidence that blanket bans are not scientifically justified.

In March 2023, United Nations Independent Expert on sexual orientation and gender identity, Victor Madrigal-Borloz, issued a formal statement criticizing World Aquatics' policy restricting transgender athletes. He argued that the ban was not based on a thorough, evidence-based assessment and that it disproportionately impacted transgender women, violating their human rights to participate in sport and non-discrimination. Madrigal-Borloz noted that the policy was introduced without sufficient consultation with trans athletes and that the scientific evidence on performance advantages remains contested. He called on international sports federations to adopt inclusive policies that balance fairness with the rights of all athletes, rather than imposing blanket exclusions.