BY STEVEN ZEITCHIK

Los Angeles Times

LOS ANGELES

--In the late '80s a thunderbolt of inspiration struck Jack Valenti, longtime chief of the Motion Picture Association of America: What if his organization got rid of the X rating, besmirched by years of misappropriation by hard-core exploitation films, and replaced it with a new marker that was both trademarked and respectable?

Thus was born the NC-17. Formally instituted in 1990, the restrictive rating aimed to signal moviegoers that a film included adult-oriented--but not necessarily pornographic--content and made those movies off-limits to anyone under 18.

Valenti had high hopes that the NC-17--he called it "unstigmatized"--would usher in an era of mainstream acceptance for films with serious adult themes. But after some initial acceptance by directors, distributors, exhibitors and audiences, the rating fell deeply out of favor with filmmakers and moviegoers alike.

Now, even as basic cable is constantly pushing into ever-more steamy and violent territory and pornography is easily available on the Web, movie theaters are practically devoid of formally adults-only films. The number of movies released with the NC-17 rating has plummeted; those that do go out with that stamp sell few tickets at the box office.

The reasons are clear: Some theater chains won't play them. A number of media outlets, particularly newspapers and TV stations in more conservative states, won't accept ads for them. Walmart and other retailers won't sell copies on DVD.

Now at 22 years old--the same age X was when it was retired--the NC-17 is seen inside Hollywood and beyond as ineffective and broken. But no one can agree on how to fix it.

"There's no question there's a stigma," said Joan Graves, head of MPAA's ratings board. "If you have any ideas on how to break it, I'd love to hear them."

At issue is more than just what grade an industry trade group should assign to a particular movie, and more than questions of revenue and profit. At its core, the debate over NC-17 is a matter of what material society considers mainstream, who gets to make those determinations and what standards they use.

NC-17's fall has been dramatic. Last year, just three such films arrived in theaters, and the highest-grossing, Fox Searchlight's sex-addiction drama "Shame," didn't even sell $4 million worth of tickets.