A castrato (plural "castrati") was a type of male singer with a very high voice. The effect was produced either through castration, or because of some hormonal problems. The word "castrato" literally means castrated. Such singers were very sought after in the early days of the opera. Most of the main soprano roles in operas by Handel and other composers of that time were written for castrati. Nowadays they are almost always sung by female sopranos, since there are no castrati left.