In some ways this was a classic scene. Two females side by side on the streetcar, one sharing her troubles -- a late alimony check, a demanding boss, unpaid bills -- and the other listening. Two females, one upset, the other comforting.

But these two females were not friends. They were mother and daughter. Moreover, the one seeking understanding was the adult, and the one extending it was the child, no more than 10 or 11 years old.

As a fellow traveler, I followed their conversation out of the city until I had to leave them on their way to a more distant suburb. But the dialogue stayed with me as I walked from streetcar stop to doorstop. It seemed to crystallize something that I have seen more than once, more than a dozen times in current life and culture: a type of emotional role reversal.

I remember when the first studies were done of teen-age mothers. Sociologists clucked at the sad comments of these girl/mothers who kept their babies because, they said, they wanted someone to love them. It was all hopelessly backward, inside out, upside down.Parents were supposed to fill needs, children to supply them.

Now that dynamic seems common, almost endemic to contemporary parents and children. Not by coincidence to movies such as "E. T." or "Firstborn" routinely portray helpless parents. Not by coincidence have television shows such as "Different Strokes," and comic strips such as "Sally Forth" featured precocious children. Bill Cosby's new entry to prime-time television is unique precisely because it stars a set of stable parents who seem to know more than their children -- indeed, to know best.

The plot of a movie, "Irreconcilable Differences," reflects the upside-down would of parent-child relationships as well as anything I've seen. The dialogue in that movie is only a slight exaggeration of what I heard on the streetcar. The mother, whose marriage has just fallen apart, turns to her child and says, "What am I supposed to do now? . . . Who's going to take care of us?" The child uncomfortably tries to reassure her mother that "most parents get divorced." This 10-year-old finally sues for the right to divorce her wildly immature parents. The theme seems to be that a child has to force parents to grow up.

Psychologist David Elkind has chronicled the phenonmenon of the child hurried into adulthood: the "adultified child." There are the same children who are now expected to be "understanding" of their elders. A group of such adultified children at Fayerweather Street School in Cambridge, Mass., offered a remarkable passage in their new book. "The Kid's Book about Parents":

"We have noticed," they wrote, "that there are many times when our parents are sad, angry, depressed, irritable, disappointed, hostile, or plain "in a bad mood." As we get older, we find better ways of dealing with them when they're in these moods." The children are now expected to "deal" with us.

I don't know precisely why many of us rush our children into role reversal or premature friendship. I suspect it is a combination of stress, isolation and the ethic of openness. An enormous number of children experience the fallout of the most common stress of adulthood -- divorce. When the nuclear family is broken down into its parts, the remains are, for better and for worse, more egalitarian. Parents' weaknesses and failures are more obvious, their needs more raw. In urban isolation, parents may have no one else to turn to.

But it's not just the result of divorce. Our children are much more likely to know about the entire range of family troubles, economic stress, health, than we were at their age. How many parents today knew their own parents' income or of their grandparents' illnesses? How many saw their parents cry?

My generation of parents doesn't believe as much in secrets. We believe in sharing. We don't believe in hiding our feelings. We believe in openness. But how many times do we unburden ourselves by burdening our children? How many times do we push them into adulthood because we are weary or feel unable to handle their dependence? Have we become the subjects of some New Yorker cartoon of parents complaining, "My children don't understand me?"

I am not a fan of rigidity or of distant, authoritarian parenting. But I see a great many pseudo-sophisticated children who need parents and not tall pals. They need to believe that grown-ups can solve their own problems, that adults are helpers, that parents are emotionally stronger. That is the point, after all, of growing up.