I never saw a naked man until high school football when I was about 15. Looking back, I'm now 29, the traumatic shock and awkwardness that I regret experiencing could have been easily disarmed if there was some man around when I was young (like 5, 6, 7) that was casually naked around me. It's not being naked that is damaging or traumitic to a child it is the attitude the adult has about being seen naked that has the potential to damage. I think it is important for a child's body image/esteem to be handled by the "naked father" than by pornography or strangers.

P.S. It's just a penis. God made it.