Just jumping in at this point, not having contributed before quite frankly surprised this topic is still raging.
Where the hurt is to a consenting adult, there is no problem - this is, one hopes - a free, but really stupid choice. Adults are allowed stupid choices, but not for others.
For myself as a minor, it was my parents' choice, not my own. Though it happened around the age of 8
years, not days.
As I was having to go in for a tonsillectomy at age 8, apparently our family doctor had misgivings about my foreskin not growing fast enough to keep up with the rest of my body (Dr. Brandt, same as Hitler's last MD, but that's purely a coincidence). I heard that French king Louis XVI had problems producing an heir because he had a physical condition which made intercourse painful; whether that involved a sluggish foreskin, I have no idea.
Anyway, being a smart kid with some sense of anatomy, I went into that surgery knowing that my tonsils were at the back of my mouth (even though I was unprepared for the ether mask). When I woke up, my throat was sore as expected, but then there were those bandages around the end of my penis. It was at least a day or more before anybody ever explained that to me. I spent all that time trying to understand how they had to go through my penis in order to get to my tonsils at the back of my mouth (oral cavity for you geeks).
Object lesson: kids know a helluva lot more than you think they do.
Then for my own two sons, it was their mother calling the shots and I didn't know why I should have any reason to object.