the distinction between elevated testosterone levels resulting from the use of prohibited substances and naturally high testosterone levels in certain female athletes has created a dual challenge for sports regulatory bodies. While the former clearly falls under the World Anti-Doping Code, the latter prompted the World Athletics to adopt specific regulations in 2011 and 2019. These regulations sparked significant legal and human rights controversies, leading to proceedings before the Court of Arbitration for Sport (CAS), the Swiss Federal Tribunal, and the European Court of Human Rights (ECtHR). This study, through a legal analysis of the relevant rulings and regulatory frameworks, finds that although such regulations may appear discriminatory at first glance, they are deemed legitimate and necessary within the context of competitive fairness in professional sport. However, their legitimacy is contingent upon adherence to the principle of proportionality, reliance on credible scientific evidence, and safeguards for the human rights of female athletes. Given the fundamental importance of the issue, the authors propose the establishment of a specialized and independent body to address matters concerning female athletes with differences in sexual development (DSD) and those with gender identity complexities. In the absence of such an institution, the World Anti-Doping Agency (WADA) could temporarily assume responsibility for overseeing and ensuring fair application of such