The family revolution of the last four decades has not been kind to American religion. Dramatic declines in marriage and fertility rates, not to mention increases in divorce, have left many congregations with dispirited, shrinking, and increasingly gray-haired flocks.

The growing secularization of American life”marked by drops in religious attendance, affiliation, and authority in the nation at large over the past forty years”is certainly due, in part, to changes in the larger culture. It owes something, as well, to the theological and moral lassitude of many churches in the face of those changes. But a large portion derives from the declining strength and integrity of the family. The recent history of American religion illuminates what amounts to a sociological law: The fortunes of American religion rise and fall with the fortunes of the intact, married family.

Not all religious traditions are equally affected by this law. A corollary might be that more-churchly religious traditions (such as the Episcopal Church) depend even more on a vibrant family culture than do more-sectarian religious traditions (such as the Assemblies of God) because so many of the churchly adherents make a habit of churchgoing only when they are married with children. This largely explains why the mainline Protestant churches have seen their fortunes fall since the 1950s, the most recent heyday of the American family, even while the more sectarian evangelical Protestant churches have seen their fortunes rise over the same period.

After almost half a century of decline, however, those in the churchly mainline”particularly those on the left, politically and theologically”still cannot see their dependence on strong families. Blinded by their desire to be both “with it” and welcoming, they continue to lend vocal support to the family revolution that is draining their congregations.

But if the arc of recent history is any indication, the religious voices now speaking out in favor of lifestyle liberalism will soon fall silent. The general law that the vitality of American religious life depends in large part on the health of American families can be illustrated by considering recent trends in religious attendance. From 1972 to 2002, the percentage of American adults in church or synagogue on any given weekend fell from 41 percent to 31 percent, according to my analyses of the General Social Survey (GSS). About 28 percent of that decline can be attributed to family change, especially the fact that fewer adults are now married with children.

These patterns are even more pronounced among young adults. Using the same data, sociologist Robert Wuthnow found that decreases in marriage and childbearing among adults aged twenty-one through forty-five were by far the strongest predictors of declines in religious attendance among young adults in this period. Indeed, Wuthnow estimates that American churches would have 6.3 million more regularly attending young adults than they currently do had today’s young Americans started families at the same rate that they did thirty years ago.

The link between religious attendance and family life is particularly strong for men. Currently, men are 57 percent less likely to attend church regularly if they are not married with children, compared to men who are married with children. Women are 41 percent less likely to attend church regularly if they are single and childless. Marriage does more than bind a man to one woman; it also ties a man to a local congregation.

The question, of course, is why churchgoing is so tightly bound to being married with children. One reason is that marriage is one of the few rites of passage guiding the transition into adulthood. Another reason married men and women are more active religiously is that churches and synagogues give symbolic and practical support to family life. In such rites as a baptism and a bris , congregations erect a sacred canopy of meaning over the great chapters of family life: birth, childrearing, and marriage. Rabbis, pastors, and priests”particularly orthodox ones”offer concrete advice about marriage and parenthood. Congregations also have disproportionately high numbers of families who put family-centered living high on their list of priorities. These families offer moral and practical support to adults adjusting to the joys and challenges of married life and starting families. Not surprisingly, men and women who are married with children are more likely to gravitate toward church than are their single peers.

Children also drive parents to church. The arrival of a child can awaken untapped reserves of love, recognition of the transcendent, and concern for the good life in men and women”all of which make churchgoing more attractive. Parents looking to give their children a moral and spiritual compass seek out congregations, Sunday schools, and vacation Bible schools. All the data show that religious attendance peaks in the population among adults with school-age children.

Finally, marriage is more likely to drive men into church than women. Because women are more religious than men, on average, and because they usually take primary responsibility for the nurture of children regardless of their marital status, women’s religious attendance depends less on marriage than does men’s. Indeed, women with and without families are more likely to be regular churchgoers than similarly situated men.

For men, marriage, fatherhood, and churchgoing are a package deal. Men’s comparatively fragile faith often depends on wifely encouragement to flower. More important, fatherhood often awakens in men a sense of paternal responsibility that extends to their children’s religious and moral welfare. Men are much less likely to identify with and be able to fulfill the responsibilities of fatherhood”including the religious ones”if they are not married to the mother of their children. This is why divorce is much more likely to drive men away from church than it is women.

The dramatic demographic changes of the past forty years, coupled with the failure of most churches to capture the attention of adults who aren’t married with children, has led many mainline Protestant leaders to heighten their calls for aggressive outreach efforts to singles and adults in nontraditional families”together with the theological innovations required to match these efforts. Sociologist Penny Long Marler makes the case for this accommodationist strategy this way: “Clearly, while bowing to the critical contributions of traditional families, past and present, congregations must cast their nets farther and more conscientiously. Otherwise, contemporary white Protestantism may be forever ‘lost in the 1950s.’ Given the realities of an aging population and a shrinking traditional family base, it is clear that a future mired in the past is really no future at all.”

Perhaps the most visible example of this strategy is the recent “God Is Still Speaking” advertising campaign from the United Church of Christ (UCC). The “Ejector Pew” commercial from this campaign has attracted attention. It depicts a WASP upper-middle-class nuclear family settling comfortably into a church pew as unconventional families”a black single mother, a gay couple, a single man, and so on”are ejected from their pews. The commercial closes with this tag: “The United Church of Christ: No matter who you are or where you are in life’s journey, you are welcome here.”

This campaign”and the larger sentiment behind it”is doubly ironic. First, despite their inclusive rhetoric, mainline Protestant congregations are actually less likely to have single parents, single adults, and married couples without children than are evangelical Protestant churches. Mainline Protestant churches attract upper-middle-class people who live in conventional families but also aspire to the progressive cultural conventions of their class, which is to say, they walk right and talk left. Evangelical Protestant churches attract working- and middle-class people who hail from a range of different family situations but who now aspire to live in accord with God’s plan for their lives.

The UCC campaign is also ironic because it embraces the trends that have been the undoing of the UCC”indeed, of all the mainline. Because they are less likely to adopt a strict and strongly supernatural religious orientation, and to offer an intense experience of communal life centered on God, churchly traditions such as mainline Protestantism depend more on the rhythms and realities of family life to draw men and women into the life of the church. The average young man raised in a Congregationalist home isn’t likely to enter his local UCC church on any day except Christmas and Easter”unless he finds himself married with children.

By contrast, sectarian traditions such as Mormonism and evangelical Protestantism offer a stricter, more vividly supernatural religious orientation and a strong sense of community grounded in their faith, which tend to command the loyalty of young adults regardless of their family status. The intense community life of more sectarian traditions is also attractive to men, women, and children scarred by the family revolution of the past four decades: A child of divorce in the United States is more likely to join an evangelical Protestant church as a young woman than join a mainline Protestant church.

This is one reason the more churchly traditions in the United States have paid a bigger price for the family decline of the past forty years. Many of the more sectarian traditions have actually prospered amid the family revolution. For example, the percentage of Americans who identified themselves as members of mainline Protestant churches fell from 30 percent in 1972 to 18 percent in 2000; over the same period, the percentage of Americans who identified as evangelical Protestants rose from 19 to 24 percent.

The sectarian groups enjoy relatively strong barriers against a culture they see as degrading and degraded”barriers that help the children born and reared in their traditions keep the faith. They also have had greater success in attracting refugees from the familial discontents of modernity than have more churchly traditions. By contrast, groups such as the UCC have less to offer in spiritual or communal terms to the spiritual refugees of our age and”given recent demographic trends”can count on fewer adults finding their way to a church pew because they want their child to identify with the Golden Rule. Moreover, their recent efforts to reach out to adults living outside conventional families are unlikely to meet with success. Progressive-minded adults living apart from marriage and children tend to live a comfortably secular life that isn’t likely to lead them to the church door.

Perhaps it is no accident that the UCC recently decided not to fund two new commercials for its “God Is Still Speaking” campaign. The church, which lost more than thirty thousand members last year, does not have the money it had hoped to raise to expand its media campaign to attract adults in nontraditional households. God may still be speaking, but it would seem that many adults who are unmarried without children are not listening.

W. Bradford Wilcox is an assistant professor of sociology at the University of Virginia and a fellow at the Institute for the Studies of Religion at Baylor University. He is author of Soft Patriarchs, New Men: How Christianity Shapes Fathers and Husbands.