Why does Mozart, in his Operas, rely on a Contralto or a Mezzo Soprano to sing i

Question:

Why does Mozart, in his Operas, rely on a Contralto or a Mezzo Soprano to sing in male roles?

I've noticed in some of his male roles, the part was originally written for a Castrato, then Cpntralto, and now women play these roles. Why did Mozart use this voice range?

Best Answer - Chosen by Asker: Because he wants a higher sound (in the case of Cherubino because Cherubino is a teenager) and the brutal practice of using Castrati was dying out (the French always refused to use Castrati). It is important to note that Mozart was not the only composer to use pants roles for women, and there are skirt roles for men.