Gallup: Two-Thirds in U.S. Prefer Birth Sex on IDs, in Athletics

“Sixty-nine percent of U.S. adults continue to believe that transgender athletes should only be allowed to play on sports teams that match their birth sex, and 66% of Americans say a person’s birth sex rather than gender identity should be listed on government documents such as passports or driver’s licenses.” - Gallup

Discussion

But of safety; you've got the immediately obvious "what if Canelo Alvarez 'transitions' and kills some of his opponents?", as well as physical differences impacting safety in any sport with physical contact, but then you've also got the question of what happens when Megan's List (sex offenders) figures out that the locker rooms and bathrooms are open to them? It's happened repeatedly already.

And then you've got the question of "what happens to sports when girls and their parents start saying 'no way' to the situation?". Remember that under Title IX, you can't have boys' sports programs if there are no girls' sports programs, and if girls' sports programs are decimated by trans participation, you've basically killed the whole kit and caboodle.

No easy choices here; either you make it a genetic thing--XX to the girls', XY to the boys'--and get certain anger from the trans community, or you open things to the trans community, and you greatly reduce sports opportunities for all.

Aspiring to be a stick in the mud.