Competitive sport is a zero-sum game where some athletes make the cut, and others do not; someone wins, and others lose. In a zero-sum competition, the inclusion of male-bodied athletes in women’s sport inevitably denies opportunities to female athletes. Claims to the contrary deny science, defy logic, and undermine Title IX.

Myth + Fact


Allowing trans-identified athletes to participate in women’s sports won’t disadvantage women and girls. Males who identify as women lose any competitive advantage over females once they start suppressing testosterone.


Suppressing one’s testosterone after the advent of male puberty can reduce a person’s athletic capacity, but it is insufficient to close the male-female athletic gap. Studies indicate that testosterone suppression does not reduce running speed to normal female levels. Nor can testosterone suppression reduce male strength to normal female levels. Indeed, studies show that testosterone suppression removes only about 5-10% of the male strength advantage, a difference that some athletes may be able to make up with rigorous athletic training. In head-to-head competitions, allowing biological males to play women’s sports will limit female athletes’ chances of success. And on teams with limited roster spots, allowing biological males to participate will take spots, playing time, and potential scholarships away from women and girls.

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