I have just finished reading a fascinating piece of reporting from an exotic territory that I have visited only on rare occasions: the young people's department at Bloomingdale's. It is, apparently, the epitome of yet another cultural convulsion being engineered by the baby boomers.

Our foreign correspondent for this report is Margaret Carlson, acting managing editor of The New Republic, who described in Sunday's Washington Post what she saw over a Labor Day weekend shopping trip to Bloomie's young teen department. She saw $464 rung up on the cash register and she saw a 12-year-old boy purchase a $112 sweater, a $95 sweater, a pair of $70 overalls, two pair of cotton pants at $46 each and two shirts at $36 each. Carlson says there are parents who will admit to spending $4,000 a year for their junior high school kid's wardrobe.

If the reaction to the article at the Sunday afternoon soccer game is a reliable barometer of public opinion, those parents had better disappear, dry up, mend their ways, or go off and form a new society someplace where the rest of us won't be infected.

There was a group of four or five mothers standing together, watching the game, which featured the preadolescent sons we had delivered into an unsuspecting world in 1975. Somebody mentioned the Outlook article, and I said I'd started reading it and then stopped when I realized it was about people shopping in Bloomingdale's for kids' clothing.

"I read it," said one mother, "and I kept getting madder and madder." The mothers on the sidelines were not pleased. They understood only too well what kind of spending pressure parents like that put on the rest of us.

One of the mothers confessed to buying her son's shirts at Bloomingdale's, and she hastily defended this on the grounds that he has to wear dress clothes to school and the shirts are of such good quality that they last all year. The rest of us could see the merit of that reasoning, but not to some of the other extravagances that Carlson reported. These ranged from parents wheeling their infants around in $400 imported strollers and outfitting their older children in $200 snowsuits and $300 Italian wool coats from boutiques catering to people who have more money than brains or whose circuits have been overloaded with guilt.

Each generation of parents has to figure out where and how to draw the line with each generation of kids, but if Carlson's article is on the mark, there are a number of yuppie parents who do not know this. Or some of them may be so affluent that they don't care. They may also be just plain stupid. If any of them are spending $4,000 a year on a kid's clothes, that possibility can't be ruled out.

Then, too, there is the possibility that some of them may be lazy as well. It takes infinitely more energy to say "no" to a kid than to say "yes." Say "yes" to an outlandish request and you're likely to hear back something like: "Thanks, Mom, you're the most terrific mother in the world." Say "no" and you will be bored to tears by an endless recitation of how much better off everyone else is than your offspring. This is the adolescent's answer to the adult's 800 million starving Chinese children line of reasoning, and it is not something most of us would willingly tune into after a hard day at work and a tedious commute home.

It takes energy and fortitude to say no and to make some attempt to raise children with a modicum of common sense in a world that has gone mad with conspicuous consumption. And it takes ingenuity: one of the best answers to adolescent acquisitiveness I ever heard of came from a father who was a few years ahead of me in the business of rearing children. His rule of thumb was to pay whatever the freight was for the item at Sears and if the kid wanted a designer version he could pay the difference in the cost himself.

Carlson quotes various experts on why parents are spending so much on children's clothes, and I would add one to the pot: A lot of yuppie parents are not only waiting until they have lots of money to have kids, but they are also having only one kid. This is like limiting Caspar Weinberger to one carrier task force.

People who spend extravagant amounts on their children make life as difficult for other parents as those who give their 14-year-olds a 2 a.m. curfew. But beyond that there is a question of morality. No kid needs $4,000 worth of clothes in a year and no kid needs a $112 sweater. Parents who have that kind of money to throw around ought to throw some in the direction of some poor kids who need it.

It's not a ticket to sainthood, but at least they wouldn't be acting like jerks.