Levels of gun violence in films rated PG-13 have tripled since 1985, according to a new study conducted by Ohio State University and the Annenberg Public Policy Center at the University of Pennsylvania. The study also found that film violence has overall doubled since 1950.

One of the researchers, part of the study, told BBC that more and more filmmakers are coming up with action-packed scripts because violence 'sells.'

"It doesn't take a lot of imagination to figure out there are going to be disturbed kids who are going to see this kind of content," said Dr. Daniel Romer, co-author of 'Gun Violence Trends in Movies.'"The problem for parents is they can no longer rely on the PG-13 rating to tell them there isn't a lot of violence in those films," Fox News reports.

For the study, Romer and his team analyzed top 30 grossing movies every year from 1950 to 2012. Out of the 945 films from the last six decades, there were 7,695 violent scenes. Some 396 of the 420 films included 783 instances of gun violence.

Researchers found that gun-related violence was steady in R-rated movies and declined somewhat in G and PG movies since 1985. But PG-13 movies now features as many gun violence sequences as an R-rated movie. Over the past two years, PG movies have actually outpaced R-rated movies.

"It's shocking how gun use has skyrocketed in movies that are often marketed directly at the teen audience," lead author and OSU psychologist Brad Bushman said in a statement Monday. "You have to wonder why we are seeing this surge in gun violence in PG-13 movies, when it isn't appearing in G, PG and R-rated films," Huffington Post reports.

Some of the recent PG-13 movies that 'had a lot of gun violence,' include The Dark Knight (2008), Transformers: Dark of the Moon (2011), Captain America: The First Avenger (2011), The Avengers (2012), The Amazing Spiderman (2012) and Taken 2 (2012).

The researchers claimed that movies with sex scenes call for a stricter rating than scenes with gun violence.

Romer advises the Motion Picture Association of America (MPAA) to reassess its ratings system to protect young viewers.

"We'd like to see those films [containing gun violence] put into the R category... or [have them] rethink how much gun violence they will show," Romer told BBC.

The study has been published in the American Academy of Pediatrics.