The way I think parents can help is through thoughtful discussion with their kids. Let them be aware of your wisdom, lessons, values, and insights instead of forcing these things on to them. Be sure to back up what you say with examples or why you believe the way you do instead of "because I say so."
That way, when confronted with whatever situation, the kids can deal with this without you being there (which you can't be all the time).
If you simply ban TV, movies, media, etc., guess what - they will find this on their own. Or are left with whatever their friends say about a topic.