The decline of mainline church membership over the last century had more to do with reproduction than theology, according to research by a trio of sociologists.
The popular notion that conservative churches are growing because mainline churches are too liberal is being challenged by new research that suggests a simpler cause-the use of birth control-explains most of the mainline decline.
Differences in fertility rates account for 70 percent of the decline of mainline Protestant church membership from 1900 to 1975 and the simultaneous rise in conservative church membership, the sociologists said.
“For most of the 20th century, conservative women had more children than mainline women did,” wrote three sociologists-Michael Hout of the University of California-Berkley, Andrew Greeley of the University of Arizona, and Melissa Wilde of Indiana University-in an Oct. 4 article in Christian Century.
While mainline churches could claim 60 percent of the total Protestant congregants in 1900, their share fell to 40 percent in 1960. Many religious observers and some sociologists attributed the drop-and simultaneous growth of conservative churches-to the lethargy of liberalism and the appeal of biblical certainty.
But simple demographics can account for almost three fourths of the mainline decline, the trio of sociologists said.
“In the years after the baby boom, the mainline [fertility] rate declined earlier than did the rate of conservatives. Only in recent decades has the fertility rates of the two groups become similar.”
The researchers studied shifts in church membership from 1900 to 1975 and the accompanying differences in fertility rates between women in conservative churches-Baptist, Assembly of God, Pentecostal, and the like-and mainline ones-Presbyterian, Methodist, Episcopal, Lutheran, etc.
They also created a demographic model that projected what would have happened to mainline and conservative memberships if the difference in fertility rates was the only factor influencing membership during the same period. “The answer is that it would look remarkably like it does in real life,” they concluded.
The trio also studied other factors that could have influenced the real-life shift in memberships. For instance, they looked at how many people switched from mainline to conservative churches during the period, and vice versa.
During most of the last century, more people moved from mainline to conservative churches than in the other direction. Conservatives were much more successful at retaining their church members, even when they married mainliners.
“The declining propensity of conservatives to convert to the mainline accounts for the 30 percent of mainline decline that fertility rates cannot account for,” they concluded.
The researchers investigated other possible causes for mainline decline-support for homosexual and abortion rights, a lower view of the Bible, a higher “apostasy” rate, and fewer conversions from outside the Christian fold. But they dismissed these other factors as “irrelevant” because none could produce numerical changes significant enough to explain the shift in church membership.
“Higher fertility and better retention thus account for the conservatives' rising share of the Protestant population,” they concluded.
However, the authors suggested, the trends underlying the mainline's decline “may be nearing their end.”
Fertility rates are now virtually the same between the two groups and will produce only a 1 percent decline in mainline membership over the next decade, they noted. “Unless conservative Protestants increase their family size or mainline Protestants further reduce theirs, this factor in mainline decline will not be present in the future.”
Moreover, fewer people are now switching membership from mainline churches to conservative ones. While 30 percent of conservatives in the 1930s had come from mainline churches, only 10 percent of those counted among the conservatives in the early '90s had made the switch, the authors said.
However, the sociologists cautioned, it will be some time before the conservatives' “demographic momentum” exhausts itself-perhaps 50 years-because those born during the conservatives' belated baby boom of the 1970s will be filling those pews for quite a while.
Associated Baptist Press