How do different sports federations currently regulate trans women’s participation and what evidence do they cite?
Executive summary
Different sports bodies have adopted a patchwork of rules on trans women’s participation: some international federations set testosterone-based thresholds for elite competition while many national and U.S. collegiate and Olympic organizations have moved toward exclusionary policies or place decisions with schools and states [1] [2] [3]. Those banning participation cite physiological advantages from male puberty and limited evidence about hormone therapy fully eliminating those advantages, while inclusion-minded bodies and advocates stress regulation, case-by-case approaches and the limited, mixed evidence base [2] [4] [5].
1. World and international federations: thresholds, science and elite-focus rules
Global federations such as World Athletics have written eligibility regulations that primarily aim to “deliver fair and meaningful competition conditions at the elite level” and typically rely on testosterone thresholds and time-on-treatment requirements to determine eligibility for women’s categories [1]. Medical reviews and guidance cited by such federations point to testosterone as the most studied marker of male physiological advantage, recommending cut points like 5–10 nmol/L used by some bodies while noting these are higher than clinical targets for gender-affirming care and that evidence about other puberty-driven advantages is incomplete [2] [1]. These federations justify regulation with scientific literature linking elevated testosterone to athletic performance but also acknowledge gaps and the need for sport-specific research [2] [1].
2. NCAA and U.S. college sport: policy shifts toward birth-assigned sex
The NCAA updated its participation policy in February 2025 to limit competition in women’s sports to those assigned female at birth, while allowing practice access for certain students and reserving autonomy for individual schools that must also follow local, state and federal law [3] [6]. The NCAA and some allied actors argue this approach protects Title IX’s goal of equal athletic opportunity for women, citing fairness concerns and the legal environment after executive actions and litigation [7] [3]. The change reflects both legal pressure from a 2025 executive order and courts wrestling with how Title IX and constitutional arguments apply to transgender student-athletes [7] [8].
3. National Olympic and Paralympic bodies: alignment with political shifts
National Olympic bodies have trended toward restrictive stances in some jurisdictions; the U.S. Olympic & Paralympic Committee implemented rules effectively banning trans women from women’s competition following the U.S. executive order, framing the move as necessary to “ensure that women have a fair and safe competition environment” [9]. These organizations point to the same physiological-advantage arguments and cite the uncertain science around puberty and long-term impacts of hormones as justification for systemwide prohibitions [9] [10].
4. State laws, federal action and the legal backdrop
A wave of state laws has banned transgender girls from school sports and some federal actions—most notably Executive Order 14201—direct federal agencies to enforce Title IX in ways proponents say reserve women’s sports for those assigned female at birth, threatening loss of federal funds for noncompliance [11] [7]. Advocacy groups and legal scholars warn that courts remain divided and that federal rulemaking and litigation could reshape or overturn these enforcement strategies, with the Supreme Court recently signaling willingness to allow state bans to stand while also seeking narrower remedies in some arguments [12] [8] [10].
5. Inclusion-focused organizations and the evidence they marshal
Advocacy groups, municipal guidance and many sport organizations emphasize individualized eligibility, anti-discrimination commitments and the public-health benefits of participation, pointing to studies showing positive mental-health and educational outcomes for trans student-athletes and arguing that many sports bodies successfully balanced fairness and inclusion without evident harms [5] [13]. These actors dispute broad-brush claims of inevitable competitive dominance and stress that much of the scientific literature calls for more sport-specific research and careful policy calibration rather than blanket exclusions [2] [5].
6. What the evidence actually shows and where uncertainty remains
The commonly cited scientific evidence focuses on testosterone’s correlation with performance and on limited studies of transgender athletes before and after hormone therapy, which some federations interpret as support for thresholds; yet systematic reviews and medical commentaries explicitly note substantial gaps about residual advantages from earlier puberty, sport-specific effects, and long-term outcomes, making definitive, universal rules scientifically fraught [2] [1]. Policy divergence, therefore, is driven as much by legal, ethical and political judgments as by conclusive science, with courts and governing bodies effectively balancing imperfect evidence against competing values of fairness, inclusion and legal compliance [2] [8] [10].