"PG-13 became a happy home for Hollywood for many decades," Kuntz says. The rating –which instructs "Parents Strongly Cautioned. Some Material May Be Inappropriate For Children Under 13" – still allows young people to see a film without adult supervision. It is a boon for the box office. Last year PG-13 brought in more money than all the other ratings combined, according to Hollywood stats-keeper Box Office Mojo, and a number of studies in addition to those released at the end of this year show that class of films is growing more violent.
"There is an increasing amount of violence in all films because the audience is demanding it," says IHS media analyst Tom Adams. "What's driving the increase at the PG-13 level is that even though R is not the kiss of death that NC-17 is, it's a huge hindrance because a large chunk of the audience going to see these films is under 17."
Fueling demand for movie violence is also the rise of video games, many of them very violent, and the growth of the international market, where action films play better than comedies and dramas.
"There is economic reason to walk the line with the raters," Adams says. However critics say filmmakers have been allowed to walk that line too closely, pointing to a trend known as "ratings creep."
Meanwhile, as the violence in PG-13 has increased, MPAA has appeared to have held a tough line when it comes to sex and profanities – whose presence in PG-13 films has remained steady, a 2010 study found – with critics taking that as a sign of hypocrisy, or at least misalignment in priorities for the ratings board.
"The only real difference between PG-13 and R are sex and profanity," Romer says.
Graves says that the most recent study to cause controversy – Annenberg's gun violence study – should be taken with a grain of salt, in that it was looking specifically at the most popular films. "The 30 top PG-13s that they said contained more violence than R really said more about where the audience was skewing and what movies they were going to see," she says.
As to calls that the ratings board be as tough on violence as it is on sex and profanity, Graves says the MPAA standards – which distinguish violence in the context of fantasy, science fiction or super hero iterations versus grittier, gorier or more realistic representations –are in line with the internal research they've done with parents.
"There's a real difference in it and we try to indicate in our ratings descriptors, try to give parents the idea of what they're going to find it that PG-13," Graves says. "All of these kids are very different. They don't have the same sensitivities, the same fears and only parents know which child is which child."
She says the board revisited the issue of profanities specifically after the R rating it gave 2010's "The King's Speech" – a film about King George VI of England and his struggle to overcome a speech impediment which included one particularly curse-laden scene –provoked derision of the system. (The film was ultimately re-released as PG-13 with the scene cut).
"We did some outreach to parents to find out if we were on the right track or if we were operating in an outmoded perception of what they thought," Graves says. "It so overwhelmingly came back that they don't want even one F-word in PG-13."
When not being accused of being too easy on violence and too hard on cursing, also dogging the MPAA is the rating board's treatment of sexual content, where some see a double standard – that scenes showing sexual pleasure as experienced by women or those in homosexual scenarios having a tougher time with the ratings than portrayals of sexual pleasure experience by a heterosexual male. Such was the focus of the 2006 documentary "This Film Is Not Yet Rated."
More recently, actress Evan Rachel Wood publicly decried the decision to remove a cunnilingus scene from her film "Charlie Countryman," allegedly to bring the film down from an NC-17 to an R. Some reviewers questioned the wisdom of a NC-17 rating for the teenage lesbian love story "Blue Is the Warmest Color," and one New York theater still admitted high school age patrons. The filmmaker behind "Afternoon Delight" – a feminist minded film about a stay-at-home mom's encounter with a young sex worker – panned the cuts she had to make to her film to secure an R rating after reading early descriptions of the explicit scenes allowed in the also R-rated "The Wolf of Wall Street."