Family affairs: fashions in family sitcoms swing between nasty and nice.

THE HANSENS, THE CLEAVERS, THE Bradys, the Huxtables, the Bundys, the Simpsons. Since the very beginning of the medium, situation comedies about families have been an important fixture on American television.

At first glance, the sitcom families of today don't look much like those of yesterday. Family Affair's Mr. French and Uncle Bill never had to worry about Cissy getting knocked up by her boyfriend the way Roseanne and Dan Connor might on Roseanne. Viewers never really knew what Ward Cleaver did for a living (he was an accountant), but they could be sure he didn't goof off and screw up at work like Homer Simpson.

In many important ways, however, sitcom families have changed very little. Sitcoms are more apt these days to show family members bickering and trading insults. But contrary to popular belief, television on the whole still portrays families as both important and loving, and parents as the ultimate authorities in the home. This positive portrayal is especially true of the most recent batch of family-sitcom hits: top-rated Home Improvement and this season's new successes, Dave's World and Grace Under Fire.

A market-driven cycle seems to have developed in sitcoms' depictions of the family. An innocuous show will capture a large share of the viewing audience, and the networks will offer up countless imitators. Many of these shows will fail, but some will succeed. Eventually, several such series will be on the air. But viewers who don't like such shows, or who have grown tired of the sameness, will want something different. Sensing this untapped market, a programmer will take a chance on something more biting. If one of these shows succeeds, it creates its own imitators, and the process begins all over.

In the beginning, sitcoms were aimed at the entire family, but the key to getting that family was to hook the adults. Accordingly, parents were depicted as wise, caring, thoughtful, and firmly in control of their homes. Children were basically obedient and polite, if sometimes a little rambunctious. There were exceptions. Leave It to Beaver's Eddie Haskell was a wiseass and troublemaker, but he was someone else's kid, not a member of the central Cleaver clan. Father Knows Best's Bud was cut from a similar, though less obnoxious cloth, but he always got his comeuppance by the end of the episode.

Family-oriented sitcoms of the 1950s and '60s rarely left the home, and they never dealt with political issues. That changed in the '70s, thanks largely to one man: Norman Lear.

Beginning with All in the Family, Lear changed the world of television sitcoms. Lear's shows--including Maude, Good Times, and One Day at a Time--addressed controversial social and political issues that had been taboo in the genre. The real world intruded into the make-believe world in ways that would have been unthinkable just a few years earlier. Edith Bunker was almost raped. Archie Bunker openly worried about being laid off during the recession. Lear's daring paid off with solid ratings, particularly among the young urban adults craved by advertisers, and his formula was soon copied by many other situation comedies.

The parent-child relationship also changed. The children in '70s sitcoms were more likely to be teenagers or even young adults than their counterparts in the '50s and '60s, who were usually in their preteens or early teens. In part, this may have been an effort to attract young adult viewers who could more easily identify with teenagers than with small children.

Television children in the '70s were also more prone to out-and-out rebellion than their predecessors. It's hard to imagine one of the Cleaver children challenging his father's political beliefs the way Mike Stivic did with his father-in-law in All in the Family. It is impossible to imagine Father Knows Best's Betty Anderson running away with a boy as Julie Cooper did in One Day at a Time.

BUT IN ONE IMPORTANT WAY SITUATION comedies didn't really change that much. Children might be more smart-mouthed and rebellious, but in the end the wisdom of the parent was proven true, the authority confirmed. Julie Cooper and her boyfriend quickly found they were incapable of dealing with the harsh life of runaways, and she eventually returned home and accepted her mother's rules. At a time when generational conflicts were tearing apart the country, it must have been reassuring, at least to parents, to see families coping with and surviving these problems.

For almost a decade, then, adult-oriented family sitcoms remained dominated by intergenerational conflicts and political debates. Eventually, people seemed to grow tired of the format. Ratings dived in the late '70s. By the early '80s, the industry's conventional wisdom declared the genre dead.

But no sooner had the conventional wisdom formed than Bill Cosby proved it wrong. Launched in 1984, The Cosby Show was a phenomenal success, helping lift NBC from third place to first in the prime-time ratings and spawning a host of imitators.

Cosby's formula was simple and very old-fashioned. He eschewed the politics and social issues that had helped kill sitcoms in the '70s--he was criticized, in fact, for portraying an affluent, untroubled black family. He returned to a '50s-style focus on well-meaning but goofy kids whose parents must constantly straighten out the messes they make. Cosby dominated the ratings for nearly a decade.

Three years after The Cosby Show went on the air, however, the first truly original sitcom in nearly 15 years showed up: Married...with Children. Finally, a sitcom dared to make fun of the central premise of all other shows of its type: that families are ultimately loving and that love provides their strength.

The creators of Married...with Children, Michael Moye and Ron Leavitt, had a long history of writing for sitcoms, and they took to the task of satirizing their previous work with a dark and gleeful relish. Al Bundy has no words of wisdom to impart to his children, which is just as well because they are too stupid to understand and too corrupt to care. Still, even this surreal and cynical show assumes the strength of family bonds. Al never cheats on his wife, even when presented with comely temptation, and he always dutifully provides for his ungrateful kin.

The show immediately caught on with young men, a group that hadn't really latched on to the Cosby-style sitcoms. And Rupert Murdoch, against the advice of the show's producers, gambled that The Simpsons--a gentler but nonetheless satirical view of families--could produce a counter-programming hit. He was right. Putting The Simpsons up against the aging Cosby Show proved a master stroke, giving the Fox network its first major hit.

Meanwhile, Roseanne brought back to television the blue-collar family, which had been missing since All in the Family. Like the parents of '50s sitcoms, Dan and Roseanne Connor keep a firm hand on their brood. But they keep that control as much with well-placed, and ultimately well-meaning, sarcasm and insults as they do with pearls of wisdom. Dan and Roseanne are smart and loving, but far from perfect. And like All in the Family, the show brings current events and issues into its fictional world.

THE LATEST BATCH OF SITCOMS SEEMS to have traded in this edginess for a more gentle humor. In the last couple of years, we've seen a contingent of sweet shows that often focus on the childish antics of adults. Their baby-boomer parent figures, like many of their viewers, are trying to balance their responsibilities as adults and parents with their desire to keep the child within them alive.

Take Home Improvement. The parents are firmly in control of the household. Both parents are equals, but one is more equal than the other. The father, Tim, is a bit of a lummox--not as all-wise as Jim Anderson of Father Knows Best or as dignified as Ward Cleaver, but not an Al Bundy-style lout, either. Tim is a well-meaning but somewhat goofy man. He takes delight in the practical jokes his three sons play and sometimes enjoys playing jokes on them. He gets upset if he isn't the center of attention.

And in a recurring bit, his attempts to make his household tools and appliances more powerful inevitably backfire. The dishwasher or the lawnmower or the weedwhacker runs out of control, wreaking havoc, after he has juiced it up. In one case, he burns down a friend's ice-fishing cabin by souping up its heater.

A recent episode focused on Tim's efforts, over his wife's objections, to get his youngest son into karate class. Although the males of the family assure the mother that karate will help the boy get into shape and learn discipline, all of the boys, and the father, are in fact excited about learning how to "kick butt." Tim inevitably gets into a minor altercation with the father of a bully in his son's class. And all the men learn that violence isn't the way to solve problems.

This show's gentle humor stands in marked contrast to the big shows that preceded it: Married...with Children, The Simpsons, and Roseanne. Home Improvement's creator, Matt Williams, was also the creator of Roseanne, but he left that series after disagreements with Roseanne Arnold over the tone of the show. Interestingly, one of the successful new sitcoms--Grace Under Fire--is a kinder, gentler version of Roseanne. This series also focuses on a blue-collar female, but the wisecracks aren't nearly as pointed; the lead character isn't nearly as tough.

In one episode, Grace gives her son a birthday present, pretending it's from his no-good (and never seen) father, whom she left after years of abuse. Because she loves her son more than she hates her ex, she wants him to believe that his father cares about him and remembers his birthday. In the real world, this episode sparked a running advice-column dispute about whether Grace did the right thing.

If history proves a guide, we'll soon see a new crop of sitcoms that replace this niceness with bite and social commentary. One possible indicator: Norman Lear is back, with 704 Hauser, set in Archie Bunker's old house. The show is less biting than All in the Family, but social issues are central to its scripts. The new family is black--which would have appalled Archie--and much of the show's plotting arises from the conflict between the liberal father and his conservative son, who has a white (liberal) girlfriend. Along with South Central, which sets a family sitcom amid the violence and poverty of South-Central Los Angeles, 704 Hauser suggests that at least some producers think America is ready to again mix race and politics with family comedy.