IT'S among the oldest of human institutions. It regularly ranks in opinion polls as the greatest source of satisfaction.
Yet many experts believe it has changed more radically in the last 30 years than in any other period in its history.
It's the institution of marriage -- the framework, countenanced by society and protected by law, that has traditionally united men and women into couples to propagate the race.
Built up through the millenniums as the foundation for family life, marriage has been the sanctuary for child-rearing, a refuge in adversity, and the basic economic unit of successful cultures.
Tightly woven into each society's religious fabric, it has usually been hedged round with taboos and bolstered with moral authority.
Yet sweeping changes in the course of a single generation -- beginning in the late 1950s, erupting in the early 1970s, and leveling off in the early 1980s -- have severely weakened the institution. All across Western society in that period, marriage rates have dropped.
Divorce rates have rocketed. Cohabitation and out-of-wedlock births have risen steadily.
Buffeted in the multiple crosscurrents of economic shifts, moral and religious revaluations, increasing sexual license, growing individualism, and new attitudes toward women, marriage itself is changing -- and men and women who a generation ago would have naturally entered and remained in marriage are walking away from the institution in vast numbers.
``At no time in history, with the possible exception of Imperial Rome, has the institution of marriage been more problematic than it is today,'' writes American sociologist Kingsley Davis in a forthcoming book on marriage.
University of Chicago economist Gary S. Becker, author of a groundbreaking book titled ``A Treatise on the Family,'' agrees.
``Probably the family has changed more rapidly in the past 30 years than any similar period in history that we know about,'' he says.
Oxford demographer David Coleman calls it ``the most radical and fragmenting change in the structure of the family which has occurred since the 16th century -- or even earlier.''
``You could say that marriage as it concerns the family is in crisis,'' says Prof. Alain Girard of the National Institute for Demographic Studies in Paris.
``At this moment, the traditional rules are exploding,'' he says. ``We're searching for something.''
How serious is the explosion?
Because of wide variations in marriage and divorce patterns among the races, between urban and rural settings, and across the different regions of America, a single picture is difficult to construct.
Recent studies in the United States show, for example, that black women are much less likely to marry than white women; that abortion is more than twice as frequent in metropolitan areas than in rural communities; and that the divorce rate for the 13 Western states is 60 percent higher than that for the nine-state Northeastern region. AFTER recent interviews with sociologists, economists, demographers, marriage therapists, psychiatrists, public-policy analysts, theologians, legislators, and married couples in the United States, Denmark, England, France, and Sweden, three broad conclusions emerge.
1. Marriage has changed profoundly. Every objective and statistical measure of marriage charts deep changes -- which, in the eyes of many experts, are having irreversible effects. A few statistics make the case:
In the year ending last April, there were 1.17 million divorces in America. Although the divorce rate has leveled and may even be declining, the last 20 years has seen a threefold increase, producing the highest rate in the Western world.
Unmarried cohabitation, which accounts for about 4 percent of all US couples, is increasingly accepted. A recent study by Christine A. Bachrach of the National Center for Health Statistics (NCHS) showed that among unmarried American women aged 25 to 29, nearly 1 in 6 was living with a male partner. In Sweden, in the 20- to-24-year-old group, 60 percent are estimated to be cohabiting; in the metropolitan area of Paris, 70 percent of 20-year-old men are said to be doing so.
In 1940, 4 percent of all US births were out of wedlock. Today the figure is over 20 percent. In Denmark the figure is 42 percent -- up from 11 percent in 1970.
If current trends continue, half of all US marriages made this year will end in divorce. Largely because of divorce, as many as 70 percent of the children born today will spend some time living with a single parent by the age of 18.
In US metropolitan areas, some 70 percent of the girls and about 80 percent of the boys are sexually experienced by age 19.
``What came out of all this jumble of 15 years' worth of experience are changes that are real and are going to stay -- because they have become socially a part of our life course,'' says Arthur J. Norton, assistant chief of the population division for the US Census Bureau and a widely respected authority on marriage and divorce.
2. The trends have recently stabilized -- and may be turning around. There are signs that the period of greatest change is behind us -- and hints of a new-found yearning for stability.
The last few years have seen marked efforts to reexamine, redefine, and recapture the values of marriage. Among the signs of change:
In recent years the US divorce rate has leveled off -- and may now even be falling. Similarly, the decline in the marriage rate seems to have bottomed out, and cohabitation does not appear to be increasing. ``Thus far I see the 1980s as a period of adapting and adjusting to those major changes of the '70s,'' says Mr. Norton. ``People are sitting back and saying, `Gee, what has happened to us?' ''
Articles touching on the more traditional values of marriage are showing up in popular American magazines. Last June, Ms. magazine featured excerpts from a book in which author Francine Klagsbrun interviewed 87 couples whose marriages had lasted 15 years or more. The same month, Psychology Today ran a story by sociologists Jeanette and Robert Lauer on their survey of 300 happily married couples who were asked to explain what kept their marriages together. In September, Cosmopolitan promo ted a story described on its cover as ``The case for saying `No' to casual sex.''
Similar evidence comes from overseas. Earlier this month, the cover story in a popular French magazine, Paris Match, focused on ``The Newlyweds'' -- citing examples of French celebrities who have recently chosen marriage over cohabitation and observing that ``the anti-marriage taboo has crumbled.'' A guest column last month in The Times (London) argued compellingly for the formation of a special-interest group to lobby for ``the normal family'' comprising a ``husband and wife living with their own children, the husband the major earner, the spouses intending and trying to stay together.''
Swedish researcher Lena Nilsson Sch"onnesson, tired of all the studies of families founded on something other than marriage, decided to restrict her latest survey to married couples -- trying to discover, she said, ``the glue that holds them together.''
Contrary to popular notions, American adults typically still live in close contact with their extended families -- and still concede that their ideas on child-rearing are largely formed by their own parents rather than by television, doctors, experts, or friends. These are the findings from a new ``Family Life Survey,'' conducted by the National Opinion Research Center (NORC) of the University of Chicago and published last month in Family Circle magazine. Other NORC surveys from 1972 thro ugh this year consistently show that about 96 percent of the those polled describe their marriage as ``very happy'' or ``pretty happy.''
3. Strong marriages are still in abundance. Many couples look on marriage as the source of tremendous fulfillment, security, and companionship.
From their modest home in Charlottesville, Va., Hattie and Melvin Wilkerson speak strongly about the values of their 48-year marriage. ``Marriage is wonderful,'' says Mrs. Wilkerson, a black woman who spent much of her married life as a cook in a home where her husband was once a butler.
``I love Melvin, and I know that he loves me, and even when things seem to be rough I knew that if we stuck together it was worth it. It hasn't always been smooth, but in the most we have had a good life together.''
Her husband, now a retired deputy sheriff, says in marriage ``you live for each other.'' He adds: ``If you're married and sit down and discuss these problems with each other, you can overcome all obstacles in your way.''
Former astronaut Dale Cox of Palos Verdes Estates, Calif., describes his 40-year marriage in terms of ``the long-range benefits of enjoying life with a member of the opposite sex.''
His wife, Patricia, agrees. She adds that building a solid marriage ``is very challenging.'' Marriage, she says, is ``a tough thing to have to work with, and I think people have to hang in with it more than they're willing to in today's world.''
Over iced tea in a New York City lunchroom, author Francine Klagsbrun says she is convinced that the turmoil in the institution of marriage ``will sort itself out.'' What gives her such hope? In writing her latest book (``Married People: Staying Together in the Age of Divorce''), she says, ``I saw too many people who were really truly satisfied in their marriage.
``I really was awed [by] the ones who handled great difficulties and stayed together.'' The book, she says, has been eagerly received -- by a public apparently keen for reassurance that getting married and staying married is still possible.
Where will these trends lead?
``I think there is fundamental change,'' says Nicholas Zill of Child Trends, a Washington, D.C.-based research organization dealing with family issues. ``And I think things are different now and will remain different, even though there's been leveling off in the decline of the divorce rates.'' He foresees no ``return to dramatically lower levels of divorce,'' but predicts instead that in the future ``sequential monogamy [is] much more likely to be the norm than lifelong marriages.''
Yet many contend that the underlying value of marriage remains intact. ``We expect most people ultimately to marry,'' says the Census Bureau's Norton. ``Historically in this country, 95 percent of all adults have married at some point in their lives,'' he explains, adding that the number will fall, but perhaps only to 90 percent.
Many even maintain that divorce itself -- because it is followed so frequently by remarriage -- is a sign of faith in the institution. The latest NCHS figures show that 45 percent of all marriages in 1982 were remarriages, up from 21 percent in 1970.
``There's a continuing belief that marriage has something to offer -- a feeling that people are liable to be better off married than not married,'' says Thomas J. Espenshade of the Urban Institute, a policy research organization based in Washington, D.C. ``If people don't find what they're looking for in a marriage with a first marriage partner, they're liable to try it again with the second and maybe the third. So the institution of marriage itself seems to be reasonably healthy.''
Other observers have reservations about that conclusion. New York marriage therapist Jessie Turberg, however, describes divorce as a ``contagion,'' saying ``it's too soon to tell'' whether the present turmoil will produce sounder marriages. BUT if the views of the younger generation are any indication, marriages in the future may sail on more-even keels. A 1981 survey of children in the United States aged 12 to 16, (sponsored by the Foundation for Child Development and the National Institute of Mental Health), shows surprisingly traditional responses.
Three out of 5 of the teen-agers rejected the idea of premarital cohabitation. And while a majority agreed that ``it should be easy for unhappy couples to get a divorce,'' more than 64 percent felt that ``when parents divorce, children develop permanent emotional problems.'' And more than two-thirds felt that ``unless a couple is prepared to stay together for life, they should not get married.''
On that point, married couples themselves appear to be in sound agreement.
``Every marriage has rocky shoals,'' says James Stewart of Farmington, Conn. Mr. Stewart, a retired senior vice-president of a major insurance company, has been married to his wife, Carolyn, for 45 years.
``If a little bit of that tends to drive you apart, there is clearly not the commitment,'' he concludes. ``I think you have to want to make it work to make sure that it does.''