Well, as a member of the media and a parent myself, I can't stress enough the need for parents to control what their kids watch. Because I can tell you right now, the industry cannot and will not do it for you. Channels with mature content all compete with each other so even if one channel wanted to curb the portrayal of violence in their shows, they'd quickly discover they lost their market share to a competitor with stronger content.

So yes, tv, movies, videogames, they all contribute because children are watching/playing things never intended for them.

Cyran0