Yeah. They have actually done pre and post transition comparisons with trans women athletes that do show a loss in performance.

And trans men do have an advantage. I'm reminded of the trans boy who was only allowed to compete as a girl in wrestling in Texas...and who won everything, proving his point about saying he shouldn't be there.

I personally think that the requirement to be on hormones for X period of time for trans women is a reasonable balance. For trans men, just let them go into the men's category, if they can't compete, that's on them ;).