-_- I think it is terrible that you refer to other women as sluts. And yes people care about appearance , males and females. It also depends on how big the birthmark is an on how it looks like in general. But chances are guys aren't going to care if your boobs are a nice size.
Almost all people care about appearance on way or another
Of course they care about appearance. But a guy would be stupid if he cared about a birthmark unless it looked seriously gross. And most birth marks don't, so. I have a small birth mark on one of my boobs, and some other ones near my boob area. The guy I'm currently seeing finds them cute for some reason. Also, not cool calling girls sluts like that.