In 1599, Pope Clement VIII gave the ok for castrated young boy's to sing in the Church. This went on for the next 280 years but it appears the practice still continues to boys who speak out about being molested by pedophile priests.  

As the castrato's body grew, his lack of testosterone meant that hisepiphyses (bone-joints) did not harden in the normal manner. Thus the limbs of the castrati often grew unusually long, as did the bones of their ribs. This, combined with intensive training, gave them unrivalled lung-power and breath capacity. Operating through small, child-sized vocal cords, their voices were also extraordinarily flexible, and quite different from the equivalent adult female voice. Their vocal range was higher than that of the uncastrated adult male.