I agree w/ this but w/ exceptions. One would be golf. Some rural areas could never, ever build a girls golf team. Even if they did, they'd have no one to play against.
But a girl might come along w/ real golf talent needing competition. I have no problem w/ her playing w/ and against boys (from the same tees).
ZERO exceptions.
None. If they want to do coed stuff, its not on official organized school or professional teams, its on their own time or in a private league where everyone there agrees to be there and agree to take the risks.