Johansson, Knightley Bare All for Mag Cover

NEW YORK – Pick up this month's Hollywood issue of Vanity Fair and you'll see two lovely young stars-of-the-moment, Keira Knightley and Scarlett Johansson, posing alluringly in the altogether. Open the foldout, and you'll even see Johansson's bare buttocks.

What you won't see is a third, equally lovely young actress, Rachel McAdams of "Wedding Crashers" fame. It seems McAdams arrived at the photo shoot and decided she didn't want to take her clothes off.

And so, sitting between Johansson and Knightley is fashion designer Tom Ford, the issue's guest editor. He nuzzles Knightley's ear and, though he shows plenty of chest hair, is fully clothed. Presumably, no one thought of asking him to disrobe.

Is it arty and fun, or does it say something about sexual politics in Hollywood? In 2006, four decades after the launch of the feminist movement, does a serious actress still need to take her clothes off to get attention?

And where, oh where, are the naked men?

The reason female stars disrobe is simple, says Janice Min, editor of the much-read celebrity magazine US Weekly. "It's tried and true. You show some cleavage on an actress. You make her look sexy. You make her look hot." She needs to be hot — because in Hollywood, "you have to be sexy to be a successful actress. You just have to be."

So where's the nude photo of Brad Pitt? Or George Clooney, who appears later in the issue, dressed, amid a bevy of women in flesh-toned bras and panties? Let's face it, Min says: Women do like to see sexy men — just not with all their clothes off.

"Men just aren't viewed as sex objects in the same way that women are," Min says. "Women don't think about men being naked in the same way that men think about women." In fact, she says, at her magazine's offices, when photos come in of a male star with no shirt on, "We say, 'Gross! Put some clothes on!'" (Imagine that being uttered about an attractive female.)

For one expert on the magazine industry, it's a little more complicated. "There's an inherent fear in this country of pictures of naked men," says Samir Husni, a journalism professor at the University of Mississippi. "We've been trained to look at pictures of naked women, but we haven't been trained yet to look at pictures of naked men."

A few male stars have blazed a trail. Burt Reynolds appeared nearly nude in Cosmopolitan in 1972. David Cassidy, in Rolling Stone, the same year. David Hasselhoff. And Ford, too. But it's a lonely group.

Husni calls the current VF cover the "Playboy" issue, because "you can call it art as much as you want — it's still naked women." Nonetheless, he says the magazine has scored huge buzz.

And buzz, in the cutthroat magazine industry, goes a long way. If a magazine sells more than 30 percent of its copies of a particular issue, it's a success. Every copy sold above that is money in the bank. And how do you sell those extras? By grabbing the first-time buyer at the newsstand. The industry rule of thumb is you have 2 1/2 seconds to grab that buyer. And you do it with the cover.

"The cover is your calling card," says Will Dana, managing editor of Rolling Stone magazine, which over the years has produced its share of memorable covers (including the iconic photo of a nude John Lennon wrapped around a clothed Yoko Ono — a rare exception to the rule.) "People are making a split-second decision. It's got to be compelling."

By that standard, the VF cover, shot by Annie Leibovitz, is a slam-dunk. Society columnist Liz Smith wrote about a dinner party where people were passing the issue around, declaring it "ridiculous ... egotistical ... absurd."

"So, I ask you, is editor Graydon Carter smart or what?" Smith wrote.

Carter, in an e-mail message to the AP, said "I chose Tom Ford with the intention of giving him a lot of creative freedom — which I did. And I was extremely pleased with the results."

The results include a 46-page photo spread in which actresses Sienna Miller, Angelina Jolie, Jennifer Aniston and Joy Bryant also appear in various states of nudity. There's also an L.A. plastic surgeon (male and dressed) appearing on a golf course next to a giant female breast. And actor Jason Schwartzman, dressed in a suit and tie, posed next to a nude model — with her head cropped out of the photo.

Vanity Fair spokeswoman Beth Kseniak said it's too early to say how the magazine is selling, but that it has scored about 3,000 new subscriptions and almost 5 million web site page views.

Some of that buzz has been negative. "The whole cover just seems faux-racy to me," says Siobhan Burns, a New Yorker in her mid-30's who reads the magazine in her office. "And why, in 2006, do women still have to take their clothes off and look pouty, rather than being heralded for their accomplishments?"

Writing in Salon.com, Rebecca Traister called the cover an "over-the-top orgy of self-love, misogyny and idiocy" by Ford. Of McAdams, who also starred in "Red Eye" and "The Family Stone" in 2005, she wrote: "There you have it, ladies, straight from Vanity Fair. We don't care if you star in three successful movies in one year; if you won't get naked for a 'threesome,' you can forget your spot in our pages!"

Vanity Fair says McAdams, 29, was well aware beforehand that the cover concept called for nudity. "At the last moment, she didn't feel comfortable with the idea," Kseniak says.

McAdams' manager did not respond to a request for comment. As for Johansson, 21, who's drawn attention for her recent performance in Woody Allen's "Match Point" as well as having her breasts groped by Isaac Mizrahi on the Golden Globes red carpet, her publicist, Marcel Pariseau, said she was happy with the magazine.

No one has suggested that Johansson or Knightley, 20, the winsome, Oscar-nominated British star of "Pride & Prejudice," were forced into anything. Yet, Min says, it was a "huge honor" for a young actress to appear on VF's cover — especially the Hollywood issue: "A lot of people would think it's better to be naked and on the cover than NOT on the cover."

So buzz-worthy was the VF cover, Min says, that her magazine went out and asked people what they thought of it.

The answer? Most thought the actresses looked better with clothes on.