Ligaments associated with the vocal cords normally grow longer during puberty. This accounts for the voice change, particularly in young men, where the cords lengthen by two thirds compared to only one fourth in women. The change is caused by increasing testosterone levels at puberty. No testosterone surge, no voice change.
Take for example, Carlo Maria Michelangelo Nicola Broschi. He was born in 1705 into an Italian family of musicians. His father, a composer and choir master, died early, and the family’s economic uncertainty may have prompted the decision for young Carlo, an already talented singer, to be castrated. At that time, castration was an accepted treatment for a hernia, but in Carlo’s case the operation was ostensibly necessitated by a fall from a horse, but the subtext was that his vocal ligaments would not lengthen.
With rigorous training, which for some castrati lasted 10 years, Carlo’s singing prowess soared, not only from talent and training, but also from the increased lung capacity and the enlarged resonating chambers of a growing adolescent. His first performance was at age 15. Using the stage name of Farinelli, he performed widely across Europe and became quite wealthy and popular–a rock star of his time. For instance, his brother composed a piece to showcase Farinelli’s virtuosity and his angelic, supernatural voice. When Farinelli performed, the audience responded with tears of ecstasy and a standing ovation for five minutes. He made regular court appearances for royalty, including nightly recitals for nine years for King Philip V of Spain. Farinelli, the most famous of the castrati singers of his time, died in 1782 at age 77.
The stimulus to produce castrati and the unbroken male voice into adult life occurred in the late 16th century in order to provide singers who could manage the growing complexity of church music. At the beginning of the 17th century, opera became popular in Italy, which increased the demand in castrati singers.
By the end of the next century, however, opera fashion had changed, so the remaining demand for castrati was for the Sistine Chapel Choir, where they sang until 1903. This terminated when the newly elected pope, Pius X, decreed, “Whenever … it is desirable to employ the high voices of sopranos and contraltos, these parts must be taken by boys, according to the most ancient usage of the Church.”
In addition to the effects of testosterone on vocalization, its absence also allows bones, including the ribs, to grow unnaturally long. This provided the castrati singers supernatural lung capacity and breathing power. For instance, listen to Alessandro Moreschi, the last surviving castrato singer. He made several solo recordings in the early 1900s, You can hear why this famous singer was called the Angel of Rome.
**********************
