A rabbi writes:
Your question could reasonably be asked about any matter of ritual behavior: what we eat, what we wear, how we pray, on what days, in which language, standing or sitting, facing East or West. . . . the list goes on and on. An equally valid question is: why does God care about bread and wine, or about any sacrament or holy act? The answer, of course, is that on some level, God [well, at least the God of the monotheistic faiths] probably doesn't care, as such, except insofar as these acts bring the human heart into communion with its Source.
One way that happens is to surrender oneself to a symbolic system of stories and rituals and ethics, all manifested in community; ritual both binds this community together and instructs it in basic values. So I believe Jews and Muslims will indeed keep circumcising their sons, because it really is one of those defining aspects of being part of the community. Some won't, of course, but in my experience, Jews who either weren't circumcised or didn't circumcise their sons later regret this if they choose to be closer to the community- without pressure they come to conclude it's something that keeps us deeply connected to our ancestors and descendants. Besides, regarding the woman who concluded that it must be "traumatic spiritually" to be circumcised- well, sure, anybody can be traumatized by anything, but I think there are plenty of spiritually whole Jewish men who are doing just fine, thank you very much.
I take all these points except one: "to surrender oneself" is one thing; to surrender a part of a defenseless infant's body is quite another. It's the consent here that troubles me - and the irreversibility of a mutilation of the most intimate and sensitive part of the body. Another reader writes that the permanent mutilation is the point:
Back when it began, the question seemed to be, what would you give up - what sign could you give - that means your devotion is totally irrevocable? Circumcision as recorded in the Bible began with Abraham and his household in Genesis 17. (The Bible records his son Ishmael as being 13 at the time). Abraham was willing to sacrifice his son Isaac purely on God's say-so three chapters later.
I think it's pretty clear, at least from a Christian persepctive, that God doesn't much care about foreskin as such. Paul practically says this in Galatians 6:15; "Neither circumcision nor uncircumcision means anything; what counts is a new creation." God doesn't care, but man does, and that was the point of there being a ritual to begin with.