Castration for the purpose of singing wasn’t ever officially legal, but that didn’t stop people from filling their choirs, and occasionally their courts, with castrati. But what caused the singers to have that beautiful voice? And what were the other effects of the operation?

The Castrati

The procedure became common in the 1500s. Private patrons, church fathers, or singing companies would either approach or be approached by the parents of a boy who stood out as the most talented singer in his church choir. This could happen anytime before the main effects of puberty, but most boys were “recruited” at age twelve or younger. It wasn’t a coincidence that the practice of castration flourished in the poorest areas and among the poorest families. Many families were facing starvation, and the opportunities for castrati were staggering. By 1589, castrati were singing for the Pope in the Sistine Chapel.


The primary effect of castration is clear. Today we know that castration prevents the formation of dihydrotestosterone. This is a form of testosterone that is more potent, having a higher affinity for receptors than regular testosterone. Exposure to the hormone causes male vocal cords to grow 63%. It also causes the thyroid, a gland that sits on the windpipe, to swell and thicken with cartilage into the noticeable bump that we call the Adam’s apple. Remove the testes and, according to autopsies performed on castrati, the vocal cords have the same dimensions as those of a female soprano.

What else happened? According to The Castrato, a book by Martha Feldman on the castrati singers, there were quite a few different outcomes. She writes, “There were high-sopranos, mezzos, and altos, strident voices and sweet ones, loud and mellow voices, more and less flexible throats, very tall men and very short, well and ill-proportioned castrati.” Different singers had different lots in life. Some sang in church, some in courts, some in traveling companies, and some retired to teach and compose. Some were low-rent singers who spent their time doing small gigs in small towns, and others spun their singing careers into positions as ministers at royal courts. Whatever their later experience, it started, generally, with one operation.

The Operation

Though castrati sang in church choirs, officially church law banned the amputation of any organ—unless it was necessary to save a person’s life. Because of the illegality of the operation we have few records of how the operation was done. Surgeons tried to remain anonymous, and parents made up stories about how their child fell off a horse or had some hunting accident that required castration. Some surgeons did believe that castration was a necessary and life-saving treatment for certain medical conditions, and it’s from them we get the most information.


Surgeons did try to use some kind of anesthesia, but opiates were rarely considered worth the risk. One anonymous source wrote that doctors would, “give a certain quantity of Opium to Persons designed for Castration whom they cut while they were in their dead Sleep . . . but it was observed that most of those who had been cut after this manner died by this Narcotick.” More often, boys were given a hot bath, then had their carotid artery compressed until they were almost comatose. Another version of the procedure started with a cold bath, to numb the area, or even a milk bath. The actual procedure didn’t involve amputation. Most doctors simply opened up the scrotum and cut the spermatic cords—the vas deferens and their surrounding arteries. Without the support of the rest of the tissue, the testes would atrophy.


The Effects

What happened after that depended on a few things: the age of the child, the competence of the surgeon, and the vagaries of the human body. There haven’t been many depictions of castrati in popular culture, but the most famous one, the film Farinelli, portrays the eponymous singer as very tall and lean. It’s half right. Most singers tended to be a little fleshy around the face, chest, and thighs—which painters concealed by painting the castrati in loose or flowing clothes and most caricaturists made fun of by painting the castrati as huge, elongated balloons with a head and legs. Another typical give-away of a castrato was the total lack of beard, paired with a resistance to male pattern baldness or even thinning hair later in life.


Farinelli’s height was, to many modern people, a counterintuitive effect of castration. Boys hit a growth spurt during puberty, so a lack of hormones should cause castrati to be shorter than average men. Some were, but a more common effect of castration was unusual tallness. Children have epiphyseal plates, or growth plates, at each end of their bones. These plates consist of growing bone tissue. At some point during a child’s late puberty, the plates “close” and are replaced with regular tissue. Castrati’s growth plates never closed, so they kept growing.


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.

The drawbacks of castration were felt later in life. Large bones left many castrati with osteoporosis, and a larger-than-average body taxed their organs. Many tended to become depressed as they aged, although it’s difficult to pin that down as a physical consequence of castration, separate from their decreasing social significance as their voice aged.


The most famous castrato was Farinelli. He lived in the 1700s, but he was still causing a stir in 2006, when a research group exhumed his remains and examined them. What they found, along with length of bone, was a build-up of bone along the forehead which indicates a condition called hyperostosis frontalis interna. The significance of this is debatable. HFI is more common in women than in men, but no one entirely knows how common. According to some medical professionals it affects 12% of the population and is almost always benign. Others think it affects a lesser percent, but that it causes terrible headaches, depression, and other mental problems. Historical reports of castrati emphasize their sensitive nature and erratic mental state—but then reports of rock stars today emphasize the same thing.


Castrati started declining in popularity in the late 1700s, but they had a very slow fall. They were singing in churches, even if they weren’t popular in operas or in popular clubs, in the 1800s, and the last Sistine Chapel castrato singer, Alessandro Moreschi, didn’t retire until 1913. In his prime, he was known as the “Angel of Rome.” Some recordings of him singing in 1902 still survive.

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