It was a bit like watching a plum turned into a prune. The producer took a book of ripe, delicious oneliners by Erma Bombeck and dried it into a cheerless two-hour television show. "The Grass Is Always Greener Over the Septic Tank," which ran last week, told the tale of an American family gradually chained to a suburban charm bracelet from which dangled a station wagon, a Little League team and a hundred-pound bag of fertilizer.

Still, sitting there, waiting for the jokes that never came, humming stanzas of "What Have They Done to Her Book?," I thought about that peculiar American creaton - the sub to all that is urban. Are the suburbs obsolete? Aren't they even funny anymore?

These subdivisions-without-sidewallks were the products of the '50s when women became wives to their houses and men hugged the highways - for the sake of the children. They were as much period pieces as Ozzie and Harriet.

Each home came with one essential appliance: a housewife. In these sprawls women were, and are, the only service industry. They are the mass transporation, the volunteer network, the pickup and delivery system, and the people assigned to the creative task of waiting.

The suburbs are an icon built to the idea that two-legged kids need chlorophyll as much as the four-legged ones. Their communities were planned to give them access to all the things officially declared to be Good for Children: backyards, new schools, other children.

Well, it's no news bulletin to say that this lifestyle came with problems for adults. But now, up to our ears in mortgages, we're even questioning the trade-offs for our kids. Suburbs may be a good place for children to "be," but a lousy place for them to grow up.

On any scale of what they call child development, we rank high the values of self-reliance, coping, responsibility, problem-solving. This is the stuff of self-confidence. But the suburbs do a better job at teaching kids how to do a back flip or hit a home run than teaching them survival skills.

For the last several weeks I've talked with suburban families from Boston to kentucky. I keep hearing parents complain that the suburb is a home land where their children have nothing to do except to be children. They are worrying about whether their communities are better at preserving childhood than preparing for adulthood.

From the moment suburban kids are born to the moment they're reborn with a driver's license, too many are unbilically attached to the parent shuttle services. For years of weekdays they belong to a community that's largely limited to a peer group. Their sense of responsibility can be dwarfed by geography: How does a 10-year-old run an errand when the store is 10 miles away? How does a 15-year-old hold a job when she can't always get to it?

Many of our kids are so protected from danger that they become afraid; so sheltered that they are unable to cope with their first harsh encounter or reversal; so unable to assume responsibility that they end up feeling responsible only to their whims.

In these mostly homogenous communities, they miss the daily encounters with people who are different. So, they only learn much later (or not at all) the ways in which people are similar.

I know that these problems don't exist in every suburb. There is also as great a difference between families as between the suburb and the city. And I'm acutely aware of the city problems that push people further out the highway lines.

Yet I think there is something admirably self-assured about a child of 11 who can make his or her way on the streetcars. There is something strong and experienced abouta n adolescent whose world includes daily associations with adults from the range of occupations and races and accents. Something more fundamentally secure about a teen-agers who can use the city as a vital resource rather than avoiding it as foreign and fearful.

It's odd, but I think true, that these suburbs, built to free children from the confinements and stress of the cities, have a set of specific emotional dimensions that both confine and shape the direction of their growth as radically as that of a bonsai tree.

And maybe that's no laughing matter.