The cutting of genitalia, especially in the very young, is a cultural practice that is widespread amongst Abrahamic religions. It is yet another behaviour that admits an evolutionary explanation as Connor Wood explains on his blog Religion and Science:
Researchers such as Scott Atran, Joseph Henrich, and Joseph Bulbulia have argued that the surprising predominance of difficult, painful, and even dangerous religious rites in human cultures across the globe may be traced back to the need to solve the basic problems of human social mechanics, especially the riddle of mutual cooperation. Since humans utterly depend on one another for survival – ostracism from a hunter-gather band is often tantamount to a death sentence – tribes and groups need to find some way to ensure that every individual will contribute responsibly. If there are too many free riders, or group members who take from the group but don’t give back, then the group will fail.
The solution, according to these researchers, is explained by what’s called “costly investment theory.” Costly investment theory states that, paradoxically, groups that demand more of their members actually fare better than those that demand less. So one way to solve the problem of ingroup cooperation is to insist that everyone who wants to join the group must do something difficult or exhausting to show their level of commitment to the collective. Once you’ve participated in a difficult or straining ritual, you’ll be more motivated to throw in your chips with that group from then on. You’ve already invested a serious chunk of energy, so it would be literally wasteful for you to back out or betray the group now.
Bodily modification, including circumcision, tattooing, and scarification, are common means worldwide of inducting new members into social groups and tribes. Because these procedures are painful and irrevocable, they’re quite literally costly investments.However, the same author goes on to actually defend the behaviour on these grounds:
This is why I think the German court’s decision [to ban circumcision before the age of consent] was a bad one. It was explicitly predicated on the sovereign right of an individual to his own bodily integrity, but that sovereign right is in turn predicated on a set of philosophical assumptions that simply do not apply beyond a fairly narrow socio-political niche. Religious and cultural practices that impinge on individual liberties can be painful and seem barbaric. But they often also fulfill adaptive functions, and we need to keep this in mind if we’re going to make good decisions about how to respond to them.There is simply no sense in which this particular defence works. As David Hume pointed out, questions concerning moral value cannot be solely derived from questions from fact. The two are simply so radically distinct in character that explicating what is does not impart to us knowledge about what should be. The so-called "Is-Ought Dichotomy" encapsulates this principle. While Connor Wood may have found an interesting explanation of why some human societies have continued to mutilate the genitals of children, often at the expense of giving children sexually transmitted diseases or rendering their genitals inoperative, that does not excuse the behaviour. Instead, we need to consider whether or not we would be better off if this behaviour simply did not exist. And if Wood is worried about the death of these religious traditions, I have only to say that those traditions which bring more pain into the world than they do good we would be better off without.
There is nothing more radically despicable than Female Genital Mutilation (FGM), a practice widespread in the Islamic world. To cut off the labia and clitoris of a small, innocent child, then to sew her vulva closed with twine, leaving a small hole for urination. To have her husband have to cut open the vagina on her wedding night in order to consummate a marriage that could only be described as utterly devoid of pleasure for the wife. After all, due to the mutilation, some of the most sensitive and sexually active parts have been cut off. In addition, due largely to the brutality of the practice, the woman's sexual organs can only be imaginably left in a tremendous amount of pain. Besides, in such cultures the wife's pleasure is considered either unimportant or secondary; she is simply there to serve the needs of the husband, whether sexual or otherwise. There is nothing short of utter disgust and contempt that I have for such a practice. To add insult to injury, Arab parents in the United States will sometimes ship their children overseas to have the ritual performed.
Male circumcision in conservative Jewish communities involves a tradition whereby a Rabbi sucks on the penis of a small child. This has recently caused a series of STD infections in babies, which proved to be lethal. No where else but religion could such a practice result. I can think of no other situation or institution in which people would pause before condemning a grown man for inserting a baby's genitals into his mouth. It really is true that religious practices enable some people to perform the most hideous practices imaginable, in this case under the full protection of the law. Please note -- this is not a practice that only occurs in certain parts of the world far removed from our first world luxury. This is routine inside heavily Semitic communities in New York City and elsewhere. And it isn't prosecuted as child abuse (or, conceivably, as oral rape) as it should be.
But, in fact, circumcision serves very little medical use in the developed world, period. The practices I've outlined above are worthy both of our condemnation and of being outlawed. But so too should people be aware that male circumcision is medically unnecessary with our modern hygiene practices and medical knowledge. The only reason that circumcision is now so common is because Christian tradition, which often demands it, is so common.
Let's not perform unnecessary cosmetic surgeries on the genitals of people without their consent. I'd think this point would be obvious by now.