Obviously this won’t work for all sports, but things like football, track, soccer, it would allow for de-gendered team, even allowing athletes with the skills but not the genetically-endowed physical attributes to have a place to play.
Note: I know very little about sports and being on a sports team, so please point out anything that doesn’t make sense.
Plenty of people with XY chromosomes can’t grow facial and have a high pitched voice well into their 20s or even after
And plenty of people with XX chromosomes shave/wax/bleach facial hair and have deep voices.
Hormones aren’t binary, there’s a bunch of different hormones that can be in a lot of different ranges
And that’s not even getting into the other options besides XX/XY
Stop trying to make everyone conform to your binary views on gender.