In light of plans to introduce this policy and the particular circumstances surrounding some boxers that competed at the Paris 2024 Olympic Games, World Boxing has written to the Algerian Boxing Federation to inform it that Imane Khelif will not be allowed to participate in the female category at the Eindhoven Box Cup or any World Boxing event until Imane Khelif undergoes sex testing.
Well, seeing as people with abnormal sex genes may have an advantage in competitive women’s sports, you would actually expect to see a significant amount of that “outlier” group in the group of top athletes, as there is a selection happening. You’re right that if you chose independently at random from people who are top athletes and people who have abnormal sex genes, the overlap would be incredibly small. But sports is not a random selection at all. At the top of sports, even the smallest advantage means the difference between winning and losing, so even small variations (like those caused by abnormal sex genes) may give significant advantages (perhaps even “unfair” advantages).
And to that, I’ll reiterate my second paragraph previously.