If it's not bizarre enough that traditional, religious patriarchy reduces to little more than "God gave me a penis, so God wants me in charge," there have been some who have argued that in order to find more favor with God, it's necessary to cut off some of those dangling bits. A eunuch still has their penis and thus retains their sign of divine favor, but castration removes the bits which make the penis more useful. So God prefers the penis, but God likes a useless penis even more. Huh?
Christianity was certainly not the first religion to create a place for castration. There is archaeological evidence pointing to religious castration going back as far as the 8th millennium BCE in Anatolia. The frequency of castration in early Christianity is disputed, but some early church leaders like Origen did treat it favorably because they believed that the above statement, attributed to Jesus in Matthew 19:12, meant that people who could accept castration should do so for the sake of the Kingdom of Heaven.
Christian castration was a curious development because as old as religious castration may be, there was little or no precedence for it in Judaism. It was, instead, an inheritance from Roman religion and pagan antiquity, thus preserving in Christianity ancient, negative attitudes towards sex which were not so extreme in ancient Judaism. Making the penis a sign of superiority and leadership helped enshrine misogyny in Christianity; preferring an unused or useless penis helped enshrine fear and hatred of sex in Christianity.
The two are not unrelated because traditional Christian misogyny and patriarchy have been tightly bound to efforts to control the reproductive powers of women. Theologians have tried to portray men as the "active" agent in reproduction and women as the "passive" agent, but nothing could hide the fact that the male role in biological reproduction is short while the female role is much longer and thus much more active. Isn't curious that promoting castration means promoting the removal of bits which make the penis useful for reproduction and which produce male hormones, such that a eunuch is in some ways closer to a woman than to a man?