Some ancient weirdness:
The First Council of Nicaea, in 325 AD, was a meeting of Christian bishops in which they tried to establish the rules and doctrines that all Christians were supposed to follow. Wikipedia says:
Its main accomplishments were settlement of the Christological issue of the divine nature of God the Son and his relationship to God the Father, the construction of the first part of the Nicene Creed, mandating uniform observance of the date of Easter, and promulgation of early canon law.
However, one of the lesser-known rules that the bishops enacted at the Council was to ban men who had castrated themselves from being in the clergy. Because, apparently, self-castration had become something of a fad among early Christians. Enough so that the bishops felt the need to put an official stop to the practice.
The historian Daniel Caner has examined this issue in his 1997 article "The practice and prohibition of self-castration in early Christianity"
Caner notes that the fad had its origin in a passage from the New Testament, Matthew 19:12, in which Jesus appears to endorse the practice of self-castration. As the passage reads in the King James translation:
For there are some eunuchs, which were so born from their mother’s womb; and there are some eunuchs, which were made eunuchs of men; and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven’s sake. He that is able to receive it, let him receive it.
Most interpreters of the Bible, ancient and modern, argue that when Jesus used the word 'eunuch' he meant it as a synonym for 'celibacy'. Apparently this was a common use of the term 'eunuch' in the ancient world.
Nevertheless, he used the term eunuch. So some early Christians decided the passage should be taken literally. In which case, Jesus seemed to be saying that, while self-castration was not appropriate for all men, for an elite few it was an ideal to strive for. Inspired by this passage, a number of men "took the sickle and cut off [their] private parts."
The most prominent Church father who was said to have castrated himself was Origen of Alexandria
(c. 185 - c. 253). But Caner notes that there was an entire sect of early Christians, the Valesians, who embraced the practice. Wikipedia says
that, in addition to castrating themselves, "They were notorious for forcibly castrating travelers whom they encountered and guests who visited them."
According to Caner, the more widely adopted Christianity became in the Roman empire, the more the Church tried to present itself as the upholder of mainstream values, and self-castration really didn't fit into that image. Therefore, "Radical manifestations of an ideal de-sexualization... became a 'heretical' threat to the orthodox community."