I believe that it is up to the maturity of the child and the way that the child handles violence, adult themes and violent language. The parents are responsible for their children and that includes the movies that they watch, not the child. Certain M rated movies are worse than others and therefore the child may be allowed to watch some M rated films and not others. However if a child is responsible, mature and sensible then they would feel more comfortable watching higher graphic movies.
I believe that it is up to the maturity of the child and the way that the child handles violence, adult themes and violent language. The parents are responsible for their children and that includes the movies that they watch, not the child. Certain M rated movies are worse than others and therefore the child may be allowed to watch some M rated films and not others. However if a child is responsible, mature and sensible then they would feel more comfortable watching higher graphic movies.