where do birthmarks come from

Most of what I can tell, this type of birthmark is gone by the time the baby is two (or so) but might still show up from time to time into adulthood when he's really good and angry. What I can't deal with is the amount of people, particularly adults who say "Why does your baby have that red mark on his face?" Or you know, "What's wrong with your baby?" My own mother went so far to offend me by saying "Are you sure we can't put some scar cream on it and make it go away? I generally say "It's just a birthmark that should be gone by the time he's two"…however, is there a way to maybe clue some clueless people in that they're being complete horse's rumps about it? And harmless, and like you said — something that will fade away on its own, with time, no scar creams (!) (and also, ?!!) or lasers required. "It's noticeable now and will grow for a year, and then it will mostly go away on its own." She even went ahead and pre-emptively answered a couple of boneheaded possible questions/comments about hats (not a good idea, just yet, because it was still growing and sensitive) and touching it (no, please don't). She took the same approach when asked about it in public, with just a shorter script: It's a birthmark, it's harmless, it will go away on its own sooner rather than later. Most people really just want to know 1) if it's harmless, or 2) if it will go away. (Though this is harder for parents dealing with a port-wine stain or disfiguring hemangioma that may require medical treatment.) If someone insists on being really rude or stupid, answer them on a case by case basis — knowing though, that the more you engage with stupidity, the 1) longer the conversation will go on, and 2) the more upset/worked up you'll be by the end of it, if you're not naturally confrontational or mouthy. But for the child's sake — if say, the mark remains noticeable at two or four or seven — treating it like you've been doing so far, in a matter-of-fact and straightforward way instead of getting all YOU ASSHOLE about every unsolicited comment, could already be teaching your son to deal with it the right way too. where do birthmarks come from where do birthmarks come from