ASK ANDY Cherlin to draw a picture of the American family today, and he would ask for three pieces of paper.
"I could not draw one picture,'' says the Johns Hopkins University sociologist who began studying families long before they became fashionable.
Cherlin would sketch, first, the family as many people still see it -- a mother, a father and their two or three children. He calls this "the family of the first marriage."
Then he would draw another kind of family -- one parent, probably a mother, and her children.
Finally, the most difficult configuration -- the family born of second marriages with its parents, stepparents, half-siblings, in-laws and multiple grandparents. "Families of remarriage might extend over three households," Cherlin says. Their portraits "might require a huge poster board."
Andy Cherlin is not an artist, but, as a student of families, he interprets clearly the writing on the wall:
"There is no one family anymore, and I doubt there will be.''
Cherlin, a professor, a researcher and an author, has been concentrating on families since the 1970s. "The family was not hot when I first got into it," says Cherlin, an engineering major at Yale in the '60s until he discovered he hated engineering.
Today, Harvard University Press is publishing Cherlin's newest book on the family. As a collection of findings on divorce, it addresses the continuing trend that has changed the picture of many American families -- Cherlin's among them -- over the last 30 years.
''Divided Families: What Happens to Children When Parents Part,'' is the first of what Cherlin and his co-author hope will be a series of little books on recognizing and understanding the changes in the family since World War II.
"We're not going to go back to the '50s,'' when mom was home and keeping the family together was a bedrock of marriage, says Cherlin. "We have to adjust to the realities of the '90s."
Among those realities:
* Personal satisfaction is now "the overwhelming standard by which to judge a marriage." The pendulum has swung as far as it can from obligation, which characterized many '50s marriages. Now, "People value marriage for the intimacy and emotional support. When that stops, they are expected to leave," says Cherlin.
Although Cherlin sees heightened interest in personal satisfaction as an advance for society -- "Our grandparents were too busy minding the store" -- he says it works against family stability. Many couples divorce because "one person feels bored or unfulfilled."
* Only a minority of fathers remain "very involved with their kids after divorce. A lot of fathers just fade away," Cherlin says.
* A stable, but high, divorce rate touches more than 1 million youngsters a year. More than 40 percent of American children will ''witness the breakup of a marriage,'' he says.
* Women entering the work force in record numbers that, because of economic necessity, increased opportunities and a shrinking supply of workers, are not likely to drop.
While writing ''Divided Families'' with Frank J. Furstenberg Jr., a sociology professor at the University of Pennsylvania and a Baltimore native, and pursuing other research on the effects of divorce, Cherlin began to experience them himself.
He and his former wife separated nearly three years ago and divorced last year.
''It is the great irony of my life,'' he says.
"My interest [in studying divorce] preceded my own divorce." Indeed, Cherlin wrote "Marriage, Divorce, Remarriage" in 1981. He is revising that book now.
Cherlin and his ex-wife have joint custody of their daughter, 11, and their son, 9. The youngsters spend four days a week in their father's home and three days with their mother, who has remarried.
''I was very worried about the kids,'' concedes Cherlin. The joint custody is, however, a success, he says.
Being familiar with the research on divorce ''has made me a better parent," adds Cherlin. "It makes me a bit more sensitive to the problems of the children.''
In their book, Cherlin and Furstenberg conclude that most children whose parents divorce adjust well. "Within two or three years, most single parents and their children recover substantially from the trauma of the crisis period. . . . And the majority of children, it seems, return to normal development," they write.
A small percentage of children suffer serious problems. Still, "a minority of a million kids a year is a lot of kids,'' Cherlin acknowledges.
With boys, problems are usually behavioral, manifesting themselves in especially aggressive acts, he says. Girls tend to internalize their feelings and may suffer depression, anxiety and lower self-esteem.