Well, I can think of this story from a couple years ago: https://www.npr.org/sections/thetwo-way/2017/02/27/517491492/17-year-old-transgender-boy-wins-texas-girls-wrestling-championship
Tl;dr; biological girl gets jacked up on testosterone and destroys girls at wrestling. Kid wanted to play in the boys league, but state rules didn’t allow it.