I'm sure that circumscising a child will not harm it in the long term - nor will feeding it formula milk (contrary to what hairbrained evangelical breastfeeding earth-mothers might have us believe). Millions, if not billions of babies thoughout the world have been fed formula milk over many many years now have thrived upon it and have grow into healthy, intelligent human beings.
Circumscision comes down to one basic fact for me. No human being has the right to mutilate another human being's body (and be quite clear about the fact that that is what circumscision entails) for their own selfish ends be they religious or otherwise. Our children are NOT our possessions. We are supposed to nuture and care for them and protect them from harm and pain to the best of our abilities until they are able to do that for themselves.
My husband is a Turkish muslim and is himself circumscised. Thankfully, we share the view that our son will not be circumscised unless and until there is a justifiable medical need to do so. If and when this situation arisies it will be done without question.
He will in no way be disadvantaged socially or emotionally by not being circumscised. If when he is old enough to make the decision for himself he expresses a wish to be circumscised we will do all we can to discuss this with him and support HIS own decision to do what he wants with HIS body.
In the meantime he will be taught to clean his penis regularly and thoroughly and will not be any less clean than a boy who has been circumscised.
If you are the sort of person who thinks it is acceptable to circumscise a baby or young child, why not give it a tattoo at the same time? That is something which is equally unnecessary and invasive in my view.