If parents are worried about their children and how their children *see* or *respect* theirselves then they need to continually support a possitive, strong, self respecting attitude about everything - positive about physical appearance, grades at school, personality and talents.
Children benefit MOST from involved, balanced and sensible parenting - not 'over-reacting' and 'over protective' parenting that often acts as a barrier to reality which lead sto shock later OR (as was for me) that act as a barrier which leads to a more deep intrigue into "why can't I?" and "what's wrong with it?"
Children will still hear about sex from kids at school. They will still develop their own opinions about self, body and image. They will still see images here and there - still hear cusswords - they will still grow up. The best thing a parent can do is encourage desired things POSITIVELY rather than discourage unwanted things NEGATIVELY.
Teaching the value and importance of self respect and personal dignity is MORE important than intervention.