It depends what you mean by "affected by" a dead body. If you mean, does it make me sad? It does. Especially if I was close to the person--seeing a person in a coffin is a reminder that they are no longer an active part of my life. So in that way, it does.
If you mean, does it frighten me or make me feel scared? Then no. To me death isn't a particularly frightening thing, so I don't mind seeing a dead body. Touching one doesn't bother me either, although I don't feel a great need to touch one either, but that's probably also due to my upbringing.
However, I think it should be an individual choice. I also don't think a child should be forced to see a dead body if s/he doesn't wish to--I know of at least one who was scarred for life by that.
