Why were (are) Eunuchs a "thing"?

As for surviving surgical procedures in ancient times, look up trepanning. People got holes drilled through their skulls, exposing the brain, to release evil spirits or whatever. Many lived long enough for the holes to heal significantly.

You don’t even need a blade or string. As Mike Rowe once discovered, teeth are all you need…

For a more recent example, and probably more fully documented than Origen, look up Boston Corbett, the soldier who shot and killed John Wilkes Booth:

“In 1858, Corbett was propositioned by two prostitutes while walking home from a church meeting. He was deeply disturbed by the encounter. Upon returning to his room at a boardinghouse, Corbett began reading chapters 18 and 19 in the Gospel of Matthew (“And if thy right eye offend thee, pluck it out and cast it from thee…and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven’s sake”). In order to avoid sexual temptation and remain holy, he castrated himself with a pair of scissors.”

“One day while he was ministering in the summer of 1858, Corbett was ogled by a pair of prostitutes, and the lower half of his body responded invitingly. He went home, took a pair of scissors, snipped an incision under his scrotum, and removed his testicles, then headed out to a prayer meeting.
In the Bible, Matthew 19:12 quotes Christ as saying “there are eunuchs who have made themselves eunuchs for the sake of the kingdom of heaven.” Corbett made himself a eunuch and didn’t check himself into Massachusetts General Hospital until he’d finished his prayers, had a full dinner, and taken a light stroll through the city that evening.”

How do castrati compare with countertenors? Here is a sample from Daniel Taylor: Daniel Taylor(countertenor) - Petits Chanteurs du Mont-RoyalCanada)Ave Maria - YouTube. I have heard him live and on radio many times. His voice is not exactly the same a woman’s and certainly not like a typical man’s. I have heard him interviewed. He is regularly asked if was gay. “Ask my girl friend” is his stock answer. He explained that when his voice started to change, his voice teacher said that he would likely grow up to be a rather ordinary tenor and offered to train him to be a countertenor. Since he wanted a singing career, he agreed and this is the result.

NB: I’ve reordered these cites from their original chronology to better address (and take issue with) the point in this case:

Any castrato (the singer musician), at least in the West, never became “that way” unless voluntarily.

Thus the “why this was considered necessary, rather than … female singers…” is at first blush a weird use of “necessary,” as opposed to “socially acceptable” and more generally is a complex and well-addressed topic of musicologists.

Not sure if this is the OP to go there though. /not snark

As you suggest, one can look up Origen, and find that the matter is most likely a scurrilous allegation, which became valorized, interestingly enough, 800 years later in the biography of Abelard, who actually started out along that road while dealing with and spiritually remaking himself after he knocked up his girlfriend.

The source text for the valorization (and pertinent of course to this OP) is Matthew 19:12:
“For there are eunuchs, that were so born from their mother’s womb: and there are eunuchs, that were made eunuchs by men: and there are eunuchs, that made themselves eunuchs [castrated themselves] for the kingdom of heaven’s sake. He that is able to receive it, let him receive it.”

ETA: The bracketed material “[castrated themselves]” was inadvertently copied by me from some trying-to-be-helpful commentator, and is neither mine nor anyone’s definitive take on the words of what is arguably–and boy have people argued–a parable, just one of those not prefaced in Dicta Sancta as being one.

I can think of a couple of possibilities:

  • Before that was written, one man was in an unfortunate accident and told the rabbi. The rabbi thought about it for a while and said “I think you better not come in - we have these strict regulations that apply to sacrificial animals, why shouldn’t the same regulations apply to humans?”

  • Before that was written, there was a fad in the Levant region for hot-fudge sundaes (why not?.. hot weather…), but they got the idea from some Greeks or Phoenicians or some other foreigners, and the translation of the recipe for the final add-on to the topping was badly mangled - and so were some of the customers.