Just to add a little to Drochit's response...films, like novels etc, may have a variety of 'themes' - ie subjects, topics or motifs. These can usually be described using a single abstract noun such as Revenge, Ambition, Jealousy and so on. Obviously, there are some themes which are unsuitable for younger viewers and, if these feature in the film, it will be categorised accordingly.
it means it is suitable with parental guidence for children of 13 and above, the query of parental guidence is because the film holds some sexual parts be it words,scenes etc that some parents may not want their children to watch,