"Whoa!" Enid gasped suddenly, watching as Bill stomped away from the table and out of the cafeteria -- with DeeDee in hot pursuit, her face drawn and her eyes wet with tears. "What in the world do you think is going on with them?"

Elizabeth didn't know. But from the expression she'd just seen in DeeDee's dark eyes, she had a feeling it was something terribly serious.

Something that wouldn't stay under wraps for long.

Is Bill and DeeDee's perfect relationship on the rocks? Can Elizabeth help patch things up? Will everything be all right? And does reading books like this -- Sweet Valley High 21: Runaway -- turn a young girl's brain to mush?

The first three questions are easy: Bill and DeeDee do break up, Elizabeth does help get them back together, and by the end of Sweet Valley High 22: Too Much in Love, life is simple and sweet.

The fourth question is a little more complicated.

"It's a generalized cliche' that young-adult romances are bad," says Judy Gitenstein, editorial director of books for young readers at Bantam Books, which publishes the Sweet Valley High series. "Serious and series doesn't have to be mutually exclusive. Romances can be as serious as any award-winning young-adult book."

"Like PG-rated movies, romances don't show the conflicts accurately between teen-agers and their parents," counters Regina Minudri, president-elect of the American Library Association (ALA). "Their characters conform to stereotyped American norms. They're not quality writing, and they provide no intellectual stimulation."

Even some of the romance editors themselves have distinctly qualified enthusiasm.

"I don't think we could expect that if they didn't have this, they'd be reading the classics," says Nancy Jackson, senior editor of Silhouette's First Love line. "But I think our kids deserve better."

Teen romances are the print equivalent of french fries: girls everywhere are gobbling them up. Defended by their publishers as being the only books some teens and preteens will read, the paperbacks have been criticized by others for vapid, yuppette characters (the 16-year-old twin heroines of the Sweet Valley High series, for instance, share a Fiat convertible), simplistic plots (all of life's problems tend to be resolved in 180 pages) and limited social range.

Such an approach is their appeal and strength, argue some defenders.

"Sure they're pablum, 'Dallas' and 'Dynasty,' but why shouldn't kids have books that are light and meaningless and ephemeral?" says Marilyn Kaye, editor of the ALA's youth services publication and the author -- under a pseudonym -- of four teen romances. "These aren't books they're going to remember in 30 years. They're throwaways."

"If these kids never go any further than romances, at least they're reading," says Ann Reit, a senior editor at Scholastic Books, publishers of several romance lines. "If you're living in the real world, you deal with reality, and the reality is that teen-age girls are interested in boys. And everybody likes a happy ending."

Most teen romances have just that. They also are squeaky clean, focus on the travails of a teen-age girl, and have a romantic interest that is all-consuming but never consummated (A typical ending: "When his lips met mine, I knew for sure that we weren't just friends any longer"). An estimated 95 percent of their readers are girls; boys are given up to other mass-market categories, such as science fiction. From a standing start five years ago, they now represent a majority of the original young-adult paperbacks being published each month.

Lines such as Sweet Valley High, Cheerleaders and Seniors reduce the basic teen romance to the level of soap opera. These are continuity series, with the same characters from book to book. The pedigree of such books is long if not particularly distinguished, dating back at least to the pulp serials of the early years of the century and, later, to the Nancy Drew and Hardy Boys mystery/adventures and various hardcover teen romance series in the '50s.

"Continuity is probably more necessary today than ever," says Bantam's Gitenstein. "Kids have more things to do in their leisure time, and sometimes libraries and bookstores come across as less appealing than, say, TV. Series are the best way to lure kids in."

Perhaps more to the point, says First Love's Jackson, "They're a hell of a lot less trouble, and they can make a quick buck."

The difference between today's young-adult romances and any similar books published in the past is the presence of the chain bookstores such as Waldenbooks and B. Dalton, where kids can buy the inexpensive paperbacks themselves.

"Chain bookstores tend to be supermarkets of books. For teen romances, they're a mechanism to force the titles out," says George Nicholson, editor-in-chief of books for young readers at Dell, publishers of Seniors. "They make shopping easy, and they don't intimidate kids. There's no one at the checkout desk saying you shouldn't buy this or buy that."

And 10- to 14-year-olds are buying these series in tremendous numbers. Sweet Dreams, with 88 books published, claims 19 million copies in print. Wildfire, with 70 titles, says 10 million have been sold. After 21 books, Sweet Valley High has 8 million in print. Cheerleaders, with only six books so far, is averaging 100,000 copies each. In a generally stagnant book-buying market, sales figures such as these are immensely attractive to publishers.

This popularity, along with the publishers' bypassing of libraries and parents to sell directly to kids, fuels the romance debate. The controversy hinges on the extent to which their readers take romances at face value, and whether they would be reading other things if they didn't have romances.

"Romances foster in young girls a feeling that they don't have an identity unless they have a boy," says S.E. Hinton, who wrote her bestselling young-adult novel The Outsiders in 1967 as a reaction against the romances of an earlier generation. "It's a backlash. Maybe the young-adult books went too far in becoming problem books. There's so much insecurity in the world today, and the romances say that if you had a boy, you'd be okay."

Robert Cormier, whose bleak young-adult novels, including The Chocolate War, I Am the Cheese and After the First Death, are the opposite of boy-crazy teen books, isn't as worried about romances as he is about movies and TV.

"The young-adult field has taken such great strides in the last few years in dealing with topics like racism, homosexuality, old taboos, social issues, that it's too bad to see this great step be so much diminished by the influx of these bland teen-age romances," Cormier says. "But I'd rather see kids reading -- even reading romances -- than playing video games."

"There's a tendency for adults to assume that all kids read literary books, when they really read lots of different things," says Dell's Nicholson. "You can read Jane Eyre one day and Sweet Valley High the next, and not have any problem. It's adults that have the problem."

Hinton rejects both arguments.

"That's like watching a kid pull out some corn chips, a bag of chocolate bars and a cola and saying, 'At least they're eating.'

"All romances are doing is training kids for an inferior taste," she adds. "They're not going to go from teen romances to F. Scott Fitzgerald."

Jackson, whose First Love line tries to include more depth and texture than most teen romances, also rejects the "as long as you're reading it doesn't matter" school of thought.

"It matters enormously," she says. "I think we can all think about quality more, and I don't think we should underestimate these kids. If you give them something other than pap, they'll like it."

Some publishers claim that reading levels have declined to such an extent that romances are all that some kids can handle. Not so, says Paul Siegel, chief of the education branch at the Bureau of the Census. "When tested, kids can read material that is more difficult than these publishers seem to be assuming," he says, citing a study by the National Assessment of Education Progress that found students' reading skills were essentially unchanged between 1971 and 1980.

The man responsible for launching Bantam's Sweet Dreams and Sweet Valley High -- the two most successful and most imitated teen romance lines -- is worried about the ultimate effect of a genre he helped launch.

"At worst," says Ron Buehl, now head of the juvenile publishing division at Simon & Schuster, "you can have a series or a book that encourages poor values . . . there's every likelihood of more of these. I've opened some real doors, and I'm worried about what could creep in.

"There are two approaches to young-adult fiction: quality and sleaze," he warns. "If sleaze predominates, the result is going to be another nail in the coffin of the culture."

Kaye, the ALA editor and romance author, was originally critical of romances. "But when I read them and saw how much better they were than when I was a kid, and when I saw how much kids wanted and needed them, I changed my mind," says the assistant professor of library science at St. John's University in New York.

"Ten-year-olds read these -- girls who are just starting to think about becoming an adolescent. They need serious books that deal with the problems of growing up, but they also need books to see that growing up is fun, and it doesn't have to be a trauma all the time."

Anita Silbey, editor-in-chief of The Horn Book, a review journal of children's and young-adult books, takes a similarly optimistic view, believing that the important thing is that young readers continue to read.

"If the romances keep people reading so that eventually they pick up the better books in the field, everyone has to be a pragmatist," she says. "I just hope no one -- parents, teachers, publishers -- sees kids reading romances and concludes that their work is done."