a_student, it seems you don't understand the human psyche very well, especially that of children.
I never claimed to be an expert on human psychology but I think if a child could see that they hurt someone, some type of feeling would come over them and I don't think it would be a good one.
This notion of hiding the private parts stays until they grow up.
Now there is an interesting point. However I don't think it really applies because when you masturbate it is in private. So I don't think that would be the cause of the original guilt. Guilt is the bad feeling you get when you knowingly do something wrong. If I do 85 mph in a 70 zone, I am knowingly doing something illegal or "wrong." Why don't I feel guilt? Because speeding doesn't effect my morale, despite the fact that I've been informed that it is "wrong." I felt guilty about masturbation without anyone ever telling me it was wrong.
[FONT="][FONT="]But once they realize that everybody, including many animals, masturbate, they no longer feel the guilt that they once associated with it.[/FONT]
[/FONT] I think it's more so becoming used to the act. The fact that everyone else does it gives a person more of an excuse to justify something that they once felt guilty over.