Should sex and violence on television or in the movies be restricted?

The problem I see with restricting sex and violence in movies and television  is that it restricts everyone whether they want it or not. I think it's a parents job to make sure their kids aren't exposed to things that will harm them. I grew up in a household where we could always watch R rated movies from a very young age and when there was adult content my mother would explain what it was. She believed in not withholding information from her kids. Because of this upbringing I was lucky enough to be informed about the world and make wise decisions because of it. There were many kids who had not the first clue on things in our world and were more vulnerable because they weren't aware of the harm it can do.