Prior to the late ’60s, there was no movie ratings system in America. Films that adhered to the content restrictions of the time received an Approved seal and were sent out into the marketplace for anyone to view. However, changing times and the arrival of foreign films that more readily addressed adult themes demonstrated that it was time for a change. The ratings G, M, and X were introduced, which were soon modified to G, GP, R, and X (GP eventually became the more widely recognized PG).
These classifications were deemed sufficient until the summer movie season of 1984 when parental outcry arose over the level of violence in the PG-rated INDIANA JONES AND THE TEMPLE OF DOOM and GREMLINS. Many felt that both films were R-level in content and not suitable for children to see unaccompanied. This resulted in the creation of PG-13, which fell between PG and R. Anyone could still see a PG-13 feature, but parents were warned that some material could be inappropriate for children under 13.
Nowadays, the majority of movies carry the PG-13 classification as it allows filmmakers to present a certain degree of violence, coarse language, and sexual content without limiting their possible audience. It makes commercial sense, but the PG-13 movies of 20-30 years ago bear little resemblance to ones bearing the rating now. Directors routinely take movies right up to the line without crossing over into R territory, which can mean the material is really top end PG-13 and would have received the more restrictive rating only a few years ago.
What can parents do? If you are concerned about the content of some PG-13 features, there are websites such as Kids-In-Mind that break down the levels of violence, language, and sex in each feature. It can be difficult to keep track of what your kids are seeing or hearing, particularly online, but it is worth exercising some degree of control until they are in their later teens and better able to process the often graphic content of films.