Transcript for Increasingly Violent Movies Spark Debate Over Rating System
headline about violence in the movies. A new report shows movies rated pg 13 have now become more violent than r rated movies were when the ratings process began BACK IN THE 1980s. Parents who have been relying on these ratings are left without a lot of help. Here's abc's david wright. Reporter: Shoot 'em up block busters like the first of the diehard movies or the original terminator used to be rated r. But their modern day sequels, pg 13 even though you now get a lot more bang for the buck. Researchers at the university of pennsylvania looked at the top grossing movies of the past 60 years, from cinderella all the way down through the hunger games, watching in particular for the level of gun violence. Our conclusion is that the rate of gun violence in the pg 13 category has gone up like three times since it first started. Reporter: In 1985 the average pg 13 had less than one shooting per hour, in 2012 nearly three shootings per hour. Sex and swearing will still earn on r rating but gun violence pg 13. A top grossing film of today will have less gun violence than a top pg 13 today. Reporter: The motion picture association declined comment. Others dispute the suggestion that hollywood is feeding a culture of violence. Gun violence in movies may have increased but in real life violent crime is at an all time low.
This transcript has been automatically generated and may not be 100% accurate.