Halba Diouf, the 23‑year‑old French sprinter who burst onto the national scene with a 100‑metre dash that hinted at Olympic promise, is now front‑and‑centre of Europe’s most contentious sporting lawsuit. In September 2025 she lodged a civil claim against the French Athletics Federation (FAF), challenging the body’s rule that forces transgender women to keep blood‑testosterone below a prescribed ceiling if they want to race in the female category. The case, which pits French anti‑discrimination statutes against World Athletics’ 2023 “scientifically‑based” eligibility framework, could redraw the rule‑book for every federation from Berlin to Barcelona.
Diouf’s transition was legally recognised by French authorities in 2021, yet the FAF’s policy – a direct import of World Athletics’ March 2023 regulation – still bars athletes who have experienced male puberty from competing with women unless they meet a strict testosterone threshold (normally 5 nmol/L) after at least a year of hormone therapy. The sprinter argues that the rule constitutes direct discrimination on the grounds of gender identity, contravening the French Labour Code’s explicit protection of that characteristic and the constitutional guarantee of equality. Under French law the burden of proof is lighter for the claimant: once Diouf shows a prima facie case of discriminatory treatment, the federation must prove the measure is objectively justified and proportionate.
The FAF’s defence, while not set out in public documents, is likely to lean on the same scientific rationale championed by World Athletics – that the testosterone limit safeguards the integrity and safety of women’s competition. In French legal terms the federation could invoke a “legitimate aim” and argue the rule is necessary and proportionate to preserve fair play. The dispute will be heard in a French civil court, but the stakes climb higher: if the judges invoke the EU Charter of Fundamental Rights, the case could be appealed to the European Court of Justice, where no precedent currently exists on transgender‑sport eligibility. In effect, Diouf’s suit may become the first high‑profile test of how EU fundamental rights intersect with sport‑specific regulations.
Across the continent, sport governing bodies have largely folded into World Athletics’ 2023 policy without publishing national‑level challenges or policy tweaks. European Athletics simply adopts the global rule for its sanctioned events, and neither the German nor the British federations have issued distinct guidance. The Court of Arbitration for Sport, which resolves roughly three hundred sport‑related disputes a year, has yet to hand down a decision comparable to Diouf’s claim, leaving the French courts to blaze the trail. The uniform reliance on a single testosterone‑based framework underscores how a French judgment could ripple through every European federation that has so far accepted the status quo.
Public sentiment is far from monolithic, especially among the sport‑watching generation. A YouGov poll conducted in February 2025 – the most recent quantitative snapshot available – shows a growing scepticism toward unrestricted transgender participation in sport. The poll, although limited to the United Kingdom, highlights three key trends: younger adults (18‑24) are shifting from outright support to “more cautious” views; women respondents are noticeably less supportive of policies that intersect with safeguarding and single‑sex spaces; and the overall debate is described as increasingly polarised. The findings can be summed up in a quick‑look infographic:
| Trend | Detail |
|——-|——–|
| Cautious shift | 18‑24 year‑olds, once the most liberal, now express reservations |
| Gender gap | Women show a sharper decline in support for trans inclusion in sport |
| Polarisation | Public discourse is moving away from consensus toward divided opinions |
With no Eurobarometer data covering the issue, the YouGov figures become the best proxy for European youth attitudes – and they suggest a climate where fairness and safety concerns carry weight in the public imagination.
If the French court rules that the FAF’s testosterone ceiling breaches anti‑discrimination law, federations across Europe will be forced to rewrite their eligibility criteria, potentially ushering in a more inclusive era for transgender athletes. Conversely, an affirmation of the rule would cement the primacy of “scientifically‑based” standards and give other bodies a legal shield to maintain or tighten similar restrictions. Either way, Diouf’s battle is set to echo far beyond the tracks of Paris, shaping not just policy but the cultural conversation about gender, sport and the meaning of fair play in a continent that prides itself on both diversity and competition.
Image Source: kenyanathlete.com
