A cross-sectional study compared the strength, power, and aerobic capacity of transgender athletes with cisgender athletes. The study included 19 cisgender men (CM), 12 transgender men (TM), 23 transgender women (TW), and 21 cisgender women (CW). Key findings showed that TW had higher oestradiol levels and absolute handgrip strength compared to CW, but lower relative jump height and aerobic capacity. TM had similar testosterone levels to CM but lower handgrip strength and aerobic capacity. These results suggest that transgender women may have lower performance in certain metrics compared to cisgender women, while transgender men may have lower performance in some metrics compared to cisgender men. The study highlights the need for sport-specific research to inform policies on transgender athlete eligibility. The study also notes that transgender athletes may have different physiological profiles due to gender-affirming hormone therapy, and that current policies may not be based on sport-specific data. The study's limitations include its cross-sectional design and potential sample bias. The findings suggest that transgender athletes should be evaluated as a distinct group in sports. The study underscores the complexity of transgender athlete physiology and its impact on performance metrics. Further longitudinal studies are needed to confirm the effects of gender-affirming hormone therapy on athletic performance.A cross-sectional study compared the strength, power, and aerobic capacity of transgender athletes with cisgender athletes. The study included 19 cisgender men (CM), 12 transgender men (TM), 23 transgender women (TW), and 21 cisgender women (CW). Key findings showed that TW had higher oestradiol levels and absolute handgrip strength compared to CW, but lower relative jump height and aerobic capacity. TM had similar testosterone levels to CM but lower handgrip strength and aerobic capacity. These results suggest that transgender women may have lower performance in certain metrics compared to cisgender women, while transgender men may have lower performance in some metrics compared to cisgender men. The study highlights the need for sport-specific research to inform policies on transgender athlete eligibility. The study also notes that transgender athletes may have different physiological profiles due to gender-affirming hormone therapy, and that current policies may not be based on sport-specific data. The study's limitations include its cross-sectional design and potential sample bias. The findings suggest that transgender athletes should be evaluated as a distinct group in sports. The study underscores the complexity of transgender athlete physiology and its impact on performance metrics. Further longitudinal studies are needed to confirm the effects of gender-affirming hormone therapy on athletic performance.