Your claims about the foreskin are totally unsubstantiated. There are many ideas about it's function, and more importantly many people in possession of foreskins think they are functional! It doesn't matter that it's anecdotal, it's a matter of body integrity. If a person says that they value a part of their body, then it is valuable.
No, if someone doesn't consent, you
have to provide a reason to override their consent. The absence of a compelling reason
not to override consent is not justification, because lack of consent is a compelling reason not to do something in an of itself*.
Again, it's a staple of medical ethics. I have studied them.
* Would you consider it right for a parent to force their child to get a tattoo? Yes, it may not have medical consequences (besides the actual risk of the procedure) but it is wrong to do such a thing, to override that child's autonomy, unless you have a compelling reason to do so which is in their best interest.
Besides which, circumcision does involve "danger to health" as does any medical procedure.
It doesn't matter whether circumcision affects the penis negatively or not. It's a matter of individual choice. Ie: the individual gets to decide what to do with their penis, not their mum and dad.
EDIT: I've already put far too much effort into this. You cannot believe an individual's autonomy is that important if you are willing to make an exception for infant circumcision. I think that's wrong, you think there's some kind of justification, perhaps that removing the foreskin is some kind of medical necessity. I think it's obviously not, because human beings have foreskins, certainly it isn't in infancy.. and on an on and on never ending. NO MORE!
I'm going to bed.