In the world of sports, grouping participants by biological sex is commonly used to avoid unfair competition. However, this has led to controversy regarding the participation of transgender athletes. The International Olympic Committee (IOC) has allowed transgender athletes to compete according to their gender dentity since the 2003 Stockholm Consensus. In 2015, the IOC updated the guidelines, removing the requirement of sex surgery, and in 2021 released a framework for inclusion and non-discrimination. However, this policy has been criticized by some organizations for ignoring the biological and scientific aspects that affect athlete performance. International sports federations, such as World Aquatics, established working groups to assess the evidence related to sex differences in sports, while inclusion policies have been adopted by many associations in the United States, including USA Swimming and the NCAA. Nonetheless, controversies remain, such as the Lia Thomas case in 2021, which sparked debate about the fairness and integrity of sports competitions Keywords: Transgender Athlete, USA Swimming,