Family Portrait With Yuppie Puppies : ONLY CHILDREN <i> by Rafael Yglesias (William Morrow: $18.95; 420 pp.) </i>

For every decade since they were born, baby-boomers have inspired books, movies and television shows that examine and explore their lives. As college students during the ‘60s, “The Graduate” set out to define their questions and doubts. In the ‘70s, hippies were out and “Saturday Night Fever” was in. Now, after “In Search of Excellence” and “Iacocca” have left the best-seller lists and after baby-boomers have their careers in order, they are having babies. Movies like “Baby Boom” and “She’s Having a Baby” and television shows like “thirtysomething” are examining how to cope with life with children.

Enter Rafael Yglesias’ new novel, “Only Children.” In it, Yglesias follows two thirty-something couples--Eric and Nina Gold and Peter and Diane Hummel--through their first five years as parents. It opens with realistic and moving scenes of childbirth and ends when their sons, Luke and Byron, are 5 years old. In between, the couples learn how to be parents as they re-examine their marriages, their careers, and themselves.

There is much to like about “Only Children.” The issues it deals with are relevant and timely. Should a woman stay home with the baby or return to work? Who changes the diapers, Mom or Dad or both? Whose career is more important? How do you balance love and marriage and your job? The two couples struggle with these questions throughout the novel, sometimes making mistakes, sometimes finding answers.

When a woman at a dinner party asks lawyer/wife/mother Diane if her husband helps with the baby, Diane answers: “Of course not.” She’s relieved that her secret is out. She thinks: “Yes, I am a failure as a feminist.”

Conversely, when Eric Gold asks for a six-week leave from his job as a Wall Street broker to help his wife with the baby, his boss remarks: “This is really Nina’s responsibility . . . despite women’s lib and all that, it’s unfair of her to expect you to earn money for the family and also take care of your son.”

Yglesias beautifully captures the double bind that this generation faces. Is it possible to be like the Diane Keaton character in “Baby Boom”--to have a baby, a business and Sam Shepard too? The characters in “Only Children” find out that having it all is not easy.

Besides these greater issues, “Only Children” also depicts the smaller trials and tribulations of parenthood. I was laughing out loud as I read the scene in which Eric and Nina have to diaper baby Luke for the first time at home. The baby squirms, the diaper seems to explode, the parents are terrified. When they are finished, the once neat room is a mess. “There were papers everywhere, colored with the strange soupy muck of their son; there were slain boxes, their entrails scattered across the floor. . . .” Yet when Nina looks at her watch, she sees that all this destruction only took 10 minutes.

Despite the humor and trauma of parenting, a book that deals with a situation that is quickly becoming cliched must be careful not to perpetrate those cliches. Do all baby-boomers really work on Wall Street? Or worry about getting their child into the best nursery school before the baby can even walk?

The issues that give this novel importance and relevance are too often clouded by the characters’ self-absorption and obsession with triviality. A movie or television show that focuses on diapering and birthday parties can get away with it more than a novel. These characters in “Only Children” are constantly and relentlessly worrying about their children’s constipation, colic and intelligence. More than once, I was reminded of a couple I know who have forgotten how to discuss anything but their daughter, Shannon. After a while, it gets boring to hear about every detail of Shannon’s toilet training and finger-painting. Although art should imitate life, there are limits and, often, “Only Children’s” attention to every detail of Luke and Byron’s childhoods clouds the more interesting parts of the novel.

Also, the two couples whose lives are followed are written about separately. Their lives intersect only briefly, and I found myself feeling cheated. Why are these two couples’ lives compared and paralleled? The intersection comes late and seems almost incidental, as if to just contrast the differences in Luke and Byron--one sweet and charming, the other a pushy bully. There is promise of an affair between Eric and Diane, but it fails and ends quickly.

This, however, feeds into the novel’s greatest flaw. None of the adults are very likable. They are always “snapping” or “shouting” at each other, silently condemning their spouses, avoiding sex or intimacy, blaming each other for everything that goes even slightly awry. More than once, I had the desire to shake them and point out how hard their spouse was trying.

On the other hand, when Yglesias writes from the children’s point of view, the book really comes to life. He perfectly captures the imagination, the fun, the illogical logic of children. As when Luke thinks: “I am Daddy’s head. I am his hair. His eyes. His ears. His nose. His mouth. I walk on Daddy’s head. I walk through the sky.” Or Byron’s joy and amazement at learning how cartoons are made. “Byron made the pages go Whoosh! And the stick man danced across, running at Byron’s thumb, right off the page!”

Read “Only Children” for what’s original about it. Beyond the cliched yuppieness, there is a real world filled with real issues and worries and a unique view of that world through the eyes of children. Read “Only Children” for a romp through a world of Snuglis, MacLaren strollers, and Nuk Pacifiers. Or if you’re a parent or parent-to-be who wants to know, as Nina Gold did, “The joys of motherhood. Are they one great lie?”