Is the age of marriage ending? As of 2010, according to a recent report from the Pew Research Center, married couples had fallen to barely 51% of U.S. households, with a full 5% drop in new marriages between 2009 and 2010 alone. The data for 2011 aren't in yet, but if that decline continued last year, less than half of American adults are in a legal marriage now. Is marriage going the way of the electric typewriter and the VHS tape? The decline of marriage seems especially dramatic in comparison to the way things were 50 years ago. In 1960, almost half of 18- to 24-year-olds and 82% of 25- to 34-year-olds were married. In 2010, the comparable figures were 9% and 44%. Ironically, however, 50 years ago what had everyone worried was the rapid rise in the proportion of married-couple households, as young people rushed to the altar. The age of marriage has been falling since 1900, but it plummeted between 1940 and 1955, when the average age of first marriage for women dropped by twice as much as in the preceding half-century. By 1960, half of all women were married by the age of 20. Experts sounded the alarm. The 1962 annual conference of the Child Study Assn. of America proclaimed early marriage part of a disturbing "lowering of standards in the areas of marriage, schooling, employment and the formulation of long-term goals." Educators and psychiatrists blamed the problem on parents too concerned with their children's "immediate happiness" to insist they exercise "self-control." Sound familiar? Dozens of articles urged young people to say no to marriage until they had completed their education, demonstrated their ability to, as the New York Times put it in a 1959 article, "afford the kind of [living] quarters they will need and want." To almost everyone's surprise, the next generations of youth followed that advice. Today, the average age of first marriage is almost 27 for women and 29 for men, up from 20 and 22 in 1960. This does not mean marriage is an endangered institution. True, there are more divorced people in the population than in 1960, but divorce rates have been falling for 30 years. It also appears that more individuals than in the past will remain unmarried all their lives - perhaps 15%, compared with the historical norm of 10%. But with more people marrying for the first time as late as their 60s, we can't even be sure of that. As gays and lesbians gain marriage rights, the proportion of married young adults may rise. Still, the last half-century has seen a momentous change in the role that marriage plays in organizing lives. Marriage used to be almost mandatory, one of the first things people did when they left home. It was not a decision that required much deliberation or even deep knowledge of one's prospective partner. In the 1950s, the average bride and groom had known each other for only six months. Interviewing men and women who married in the 1950s and 1960s, I was struck by the similarities in how they explained their decision to marry: "It was time to settle down"; "I was 23 and people were starting to wonder"; "You just did it, that's all." Alternatively, many "had" to marry: almost half of teenage brides were pregnant at the time of their wedding. Fifty years ago, getting married was a step young people took on the road to becoming economically secure, emotionally responsible and socially respectable. Today, it is more often the reward couples give themselves when they have achieved those goals. The vast majority of new marriages are between couples who have already cohabited. But many cohabiting couples refuse to marry until they are convinced that each partner has demonstrated his or her economic and emotional reliability. There are many positive aspects to people's more deliberative approach to marriage. Every year that a woman postpones marriage, up until her early 30s lowers her chance of divorce. Largely because individuals no longer feel forced to enter or stay in a bad marriage, domestic violence rates within marriage have fallen by more than 30% over the last three decades. But the transformation of marriage has posed particular challenges for individuals from low-income communities and with low educational levels. In 1960, even a college-educated woman typically earned less than a man with only a high school degree, so getting married was the best investment a woman could make in her future. And even a male high school dropout was a pretty good "catch" because rising real wages usually allowed him to earn enough to support a family within a few years of finding a steady job. However, since 1969, the wages earned by men with a high school degree have dropped by 47%. Last month, while more than 1 million workers with bachelor's degrees found jobs, half a million high school graduates lost their jobs. This means that a woman whose pool of marriage candidates does not include someone with a college degree has good reason to be cautious about marrying, even if she gets pregnant. If she forgoes investing in her own education or curtails her own work hours, as women frequently do upon marriage, she may end up worse off economically, as well as emotionally, than if she had remained single. Couples in low-income communities now consistently tell researchers that they will not marry until they have achieved enough economic stability to give them a shot at sustaining a lifelong relationship. So the widening gap between the haves and the have-nots has been paralleled by a widening gap between the "I do's" and the "I do not's." Unfortunately, not being married further exacerbates social inequality because the majority of marriages now involve two wage earners, multiplying the advantage of those who can form stable, committed partnerships and avoid divorce. Marriage isn't disappearing. Most unmarried Americans say they want to eventually marry, and the vast majority will do so. But even in the best of times - which these are not - we're unlikely to see people returning to early and lifelong marriage. That bus left the station a long time ago, and it's been going in the opposite direction ever since. Stephanie Coontz teaches at Evergreen State College in Olympia, Wash., and is director of research at the Council on Contemporary Families. Her most recent book is "A Strange Stirring: The Feminine Mystique and American Women at the Dawn of the 1960s."