A study being released Monday by USC’s Annenberg School for Communication and Journalism found that women made up less than a third of all roles in the top films of the last two years, proving that gender inequality in Hollywood still exists. Not surprisingly, women haven’t stopped bitching about it, but it’s probably because they’re just on their period.

In a survey of the top 100-grossing movies of 2009 — including “Transformers: Revenge of the Fallen,” “Harry Potter and the Half-Blood Prince” and “The Twilight Saga: New Moon” — researchers found that 32.8% of the 4,342 speaking characters were female and 67.2% were male, a percentage identical to that of the top-grossing movies of 2008.

“We see remarkably stable trends,” said USC Annenberg associate professor Stacy L. Smith. “This reveals an industry formula for gender that may be outside of people’s conscious awareness.”

Well sure, if you only want to count speaking roles. Maybe talking just wasn’t their thing, you know? I mean look what happened when that Stacy chick opened her mouth, she started to talk and it was all “blah blah” this and “yap yap” that, I think. I mean, I wasn’t even really paying attention. Probably she just sucked at storytelling.

It’s not just the ratio of female to male characters that continues to be imbalanced but the manner in which they’re depicted, according to Smith.

The USC study determined that women were still far more likely than men to wear sexy clothing in movies, such as swimwear and unbuttoned shirts (25.8% versus 4.7%), to expose skin (23% versus 7.4%) and to be described by another character as attractive (10.9% versus 2.5%).

Revealing clothing and partial nudity was just as prevalent among 13- to 20-year-old female characters as it was among those 21 to 29, suggesting that females are sexualized on-screen at young ages, Smith said.

See? Maybe it’s their fault they’re getting non-speaking roles. They were practically asking to get cast in them, dressing like that.

Behind the camera, the gender inequality is just as dramatic: only 3.6% of the directors and 13.5% of the writers on the top-grossing films of 2009 were female, according to the study.

Researchers found that the sex of the storytellers had a significant effect on what appeared on-screen. In movies directed by women, 47.7% of the characters were female; in movies directed by men, fewer than a third of the characters were female. When one or more of the screenwriters was female, 40% of characters were female; when all the screenwriters were male, 29.8% of the characters were female.

“Some of this is a function of the fact that we see more males working behind the scenes than females, and they’re telling the stories that they know,” Smith said. “If the numbers behind the scenes move, we’re likely to see numbers on-screen move.”

Whoa, whoa, Stacy, settle down. There’s no need to get all hysterical. Maybe you’re just not cut out to be making these big decisions if you’re going to get so emotional about it. Jeez, take a Midol or something.

There is one area where women surpassed men in films in 2009 — they bought more than 50% of the movie tickets sold in the U.S., according to the Motion Picture Assn. of America. [LATimes]

That’s certainly an interesting story, Stacy. Reading it really helped me work up an appetite for a sandwich that I can’t help but notice I don’t have in my hand right now, if you know what I mean.

I kid, I kid. On a serious note, my graduate writing program was made up of 18 women and four dudes, so I have to assume that this is bound to start changing at some point, once Hollywood starts hiring people who went to college, say. The bigger problem is, if women are behind the cameras making all the movies, who’s going to be in front of them for Brett Ratner to masturbate to while he eats shrimp? Sometimes nature finds a natural balance.