Sod it, I've reverted to an old user name to post this in answer to Andrewofgg and Pickle:
My son's school had a very popular all-boys/male staff choir, for broken voices only. Then his year acquired a transboy who wanted to sing in it.
So the music staff nicely, understandingly, kindly changed the repertoire to accommodate a soprano, even though the boy trebles weren't allowed to take part. Then, to even the parts out or maybe make the child less conspicuous, some of the female staff started to sing with the choir.
In a single year, the choir became less of a magnet for the boys, and something rather special was lost.
Previous years had nearly 30 boys in the all-boy choir, many taking singing lessons and performing in the school musical. This year has a small handful still singing, none taking lessons, very few getting on stage - it's a shame.