IO9: What Did It Mean To Be A Castrato? “It wasn’t just the length of the legs and the arms that changed. Castration was associated with larger growth in the chest, the jaw, and even the nose. The voice of a young boy, well trained in singing, was backed by the chest and lungs, and “resonating chamber” of a larger than average man, giving the best singers not just a high voice but power to back it.”
I’m certainly not advocating it, but if a boy (who can sing) does need to be castrated for some reason, there would be a lot of curiosity in knowing just what he would sound like.