Before Felicity and Dawson and Buffy, before Julia and Amanda, there was only Brenda Walsh, pouting and plotting and sunning herself on the screen in "Beverly Hills 90210."

In 1990, the infant Fox network gave birth to a new kind of show: the prime-time teen drama. These hour-long shows sought to capture the attention of a cohort of viewers that was ignored by the major networks, kids between the ages of 12 and 17. Fox hoped to lure these middle- and high-school students away from their homework, away from the phone, and put them in front of the television by using soap opera-like serials featuring teen life. And it worked.

In fact, it worked better than anyone at Fox could have dreamed. Kids made "Beverly Hills 90210," the first teen drama, an instant breakaway hit. Three seasons later, Fox launched a spin-off of "Beverly Hills 90210" called "Melrose Place," which became, improbably, another roaring success. Three seasons after that, the network introduced "Party of Five." Ten years after Brenda Walsh first graced suburban living rooms, the three shows have been cancelled into syndication. But Fox remains the unofficial network of Generation X.

Ironically, just as Fox was securing its grip on twentysomethings, another impudent weblet, the Warner Brothers television network, determinedly calling itself "the WB," has grabbed a hold of the leading edge of Gen Y-the kids born after 1979. And they've done it by using Fox's signature formula. In 1997, "Buffy the Vampire Slayer" premiered on the WB. It was only a mild success until it was paired in its sophomore season with a new show, "Dawson's Creek."

The duo provided the young network with its first dose of ratings power among teen viewers. "Dawson's Creek" instantly became the most talked about show in homerooms across the country, and this past fall, with the beginning of another teen drama, "Felicity," the WB has taken absolute control of the Gen-Y audience: The network owns five of the twelve shows most watched by viewers between the ages of 12 and 17.

But for all the similarities in the creation and marketing of these shows, the actual content of the Gen-Y programs is strikingly different from that of the Gen-X programs. And that difference may be indicative of a fundamental cleavage developing between the two generations.

At their core, the teen dramas of Gen X all have two themes in common: the struggle to escape youth and the acceptance of amorality. The first theme was the entire basis for "Party of Five," for instance, once the most critically acclaimed of all the Fox teen dramas. "Party of Five" centered around the Salinger family, whose parents were suddenly killed in a car accident. Unwilling to have the family split up by Social Services, the five brothers and sisters are forced to live together under one roof without any adult supervision.

Instead of degenerating into young savages, the children are forced to grow up fast. The oldest, Charlie (played by Matthew Fox), becomes a father figure at the age of 25; his younger sister Julia (Neve Campbell) gets married by the end of high school; Bailey (Scott Wolf) drops out of college to run the family business; and little Claudia (Lacey Chabert) becomes a caretaker for the infant Owen while still in middle school. There is no childhood for the Salingers; in fact, the family seems to flee from the idea of youth as if it were a curse or a sign of weakness.

"Melrose Place" embodied the second theme. The hallmark of "Melrose" was the constant fall and redemption of its characters: everyone is bad and good at the same time. The most popular character, Amanda Woodward (Heather Locklear) has been an audience favorite precisely for this reason. She vacillated between being the hated über-vixen slapping the faces of men who displease her, and being a pitiable waif looking for real love and happiness-neither of these personalities viewed more critically than the other.

This rampant amorality was most striking in that no one ever thought to condemn it. It was much a part of the show's topography as the apartment complex that gave the series its name.

"Beverly Hills 90210" included both themes-Brenda, the '90s teen icon played to jaundiced perfection by Shannen Doherty, was the embodiment of these stock Gen-X characteristics, a full-fledged force of adult wickedness set loose in an adolescent world. Never once did Brenda concern herself with any aspect of teen-age life; instead, her existence was spent plotting sexual escapades and social manipulation. In fact, none of the characters of 90210 ever worried about school or grades or getting asked to the prom. They weren't children: they were miniature adults playing games in a social microcosm without rules.

In stark contrast, the teen dramas of the WB embrace both youth and morality. The characters in "Felicity," "Dawson's Creek," and "Buffy" all do the things real teenagers do-break curfews, study for tests, and plead with their parents to be allowed to go out on dates.

No one in any of these worlds is eager to grow up any faster than they have to.