When we were little, whenever a sex scene came on in a movie, my dad would holler "INAPPROPRIATE!" and my brother and I would run out of the room screaming:
What impact this had on our sex lives I don't know, but I do know that as adults my brother and I obviously have to scream this at random intervals whenever we're together. These things make an impression. A piece on MSNBC talks about the dynamics of watching TV together. And forget Where the Wild Things Are. New findings suggest that watching TV with parents can freak kids out.