Well, if the kid's dad being a blood spatter specialist is a problem, then all children of, say, surgeons out there should be messed up. But we aren't, because our parents do not bring us to work to watch gross/scary stuff (well, most of them don't, can't speak for everyone) (also, children on farms etc see a lot of nasty shit, I'm guessing, but they get through it just fine?). Just like a Dexter pretending to be normal probably wouldn't bring a potential kid to a crime scene.