When Francine Pascal, the elusive creator of the Sweet Valley High books, set out to write the first few titles in the series in the early '80s, the teen-girl fiction market was wide open. "The field almost didn't exist, actually," she said last week from her home in New York. There was Young Adult fiction, which she also wrote, but that was a grittier, more urban and literary genre, and not gender-specific. For girls exclusively, she argued, there had been nothing new since Nancy Drew was invented in the '30s.

And so she ventured to write a sort of chaste Dallas for teens. She set her narrative in the fictitious, idyllic town of Sweet Valley, Calif., and she put a pair of beautiful, blond teenagers at the heart of the action. "I decided that the best characters would be twins," she said, "a good one and a bad one." Jessica Wakefield was the original mean girl: the flaky, snobbish head cheerleader. Elizabeth, her identical sister, was brainy and, according to Pascal, "the best friend you could have." In each Sweet Valley story, a social conundrum was neatly resolved, and the mean girl always did the right thing in the end. The books sold so well that Pascal and her team of writers could hardly crank them out fast enough.

Still, as squeaky clean as they seem by today's standards, Sweet Valley High books were denounced by critics at the time as trashy and shallow. "Librarians were my first foes," said Pascal. The response, in fact, was not unlike the kind of criticism that's been levelled at the newest wave of teen-girl books.

Ever since the CW network announced it would produce a TV adaptation of the best-selling series Gossip Girl(which CTV now airs Tuesday nights in its youth-friendly 7 p.m. time slot), the genre has attracted renewed attention, much of it negative. Although many of the books look rather like Sweet Valley High -- with their candy-coloured packaging and glossy cover photos -- inside, they reflect the high-stakes, low-standards universe of today's teen culture, with storylines that could have been ripped directly from the tabloids.

There is The Clique series, created in 2004 by Toronto native Lisi Harrison and featuring book titles like Dial L for Loser and Best Friends for Never. Its five spoiled-rotten, morally vapid 12-year-old heroines -- a.k.a. The Pretty Committee -- from the posh suburb of Westchester, N.Y., speak in "Ehmagawds!" and "Ah-mazings!"(The Clique is now being made into a feature film.)Similarly, Gossip Girl, marketed to slightly older girls, chronicles the lives of teen socialites on Manhattan's Upper East Side: their clothes, their love lives, their substance-abuse problems and cruel high-tech rivalries. Over on the West Coast, The A-List by Zoey Dean is set in a posh Beverly Hills high school, where name-dropping, fake pregnancies and rehab are familiar pastimes. Each series has sold more than a million copies. "We're seeing double-digit increases in teen sales for the past few years," says Lisa Huie of Indigo Books & Music.

The girls at the heart of these novels expend their energies angling to get to the top of the social ladder, no matter whom they have to devastate on their way up. There's a profound cynicism about them, says Gisèle Baxter, an English professor at the University of British Columbia, who specializes in young people's literature. "Their whole attitude puts me in mind of some teen girl's version of Bret Easton Ellis's American Psycho, only without the horror or the satire." Even the approach to sexuality is calculating and callous, say critics: "This is not the frank sexual exploration found in a Judy Blume novel," Naomi Wolf wrote in the New York Times, "but teenage sexuality via Juicy Couture, blasé and entirely commodified."

"[With these series], I think girls have been given permission to be meaner," says Lyn Mikel Brown, a professor of education at Colby College in Maine, and the co-author of Packaging Girlhood. "They're being told that this is how girls show their power. It's been valourized." But it's at least a good thing that they're reading, right? "Oh please," says Brown. "Garbage in, garbage out. We are what we take in." Even Harrison, who now lives in Laguna Beach, Calif., agrees. "I'm terrified of half the girls that read my books," she says.

That's because this generation of girls -- like every generation that came before them -- can be terrifying. Although the scale of psychological warfare in these books may be exaggerated -- this is, after all, a world in which seventh-graders get spray tans and eyebrow waxes at Bergdorf's -- the central issues of self-esteem, consumerism, sexuality, and drug and alcohol experimentation are the same-old same-old, and still as creepy as ever for grown-ups. Before Stephanie Savage, co-creator of the Gossip Girl television series, set out to make the show, she spent a week hanging out with wealthy private-school girls in New York for research purposes. "One of the things that the girls all said is that the stuff that happens in Gossip Girl is not made up," she says. "It's out there, but it just doesn't happen all the time and to everyone." The show, like the book series, is just another high-voltage re-enactment.(As a bonus, central casting at the CW network could not have chosen a better set of androgynous-chic, real-life names for its Gossip Girl cast members: Leighton Meester, Blake Lively, Penn Badgley, Taylor Momsen, Chace Crawford.)