Fox News: When Margie and Stephen Zumbrun were battling the urge to have premarital sex, a pastor counseled them to control themselves. The couple signed a purity covenant.

Then, when the two got engaged and Margie went wedding dress shopping, a salesperson called her "the bride who looks like she's 12." Nonchurch friends said that, at 22, she was rushing things.

The agonizing message to a young Christian couple in love: Sex can wait, but so can marriage.

"It's unreasonable to say, 'Don't do anything ... and wait until you have degrees and you're in your 30s to get married,'" said Margie Zumbrun, who did wait for sex, and married Stephen fresh out of Purdue University. "I think that's just inviting people to have sex and feel like they're bad people for doing it."

Against that backdrop, a number of evangelicals are promoting marrying earlier, nudging young adults toward the altar even as many of their peers and parents are holding them back.

Couples like the Zumbruns are caught between two powerful forces -- evangelical Christianity's abstinence culture, with its chastity balls and virginity pledges, and societal forces pushing average marriage ages deeper into the 20s.

The call for young marriage raises questions: How young is too young? What if marriage is viewed as a ticket to guilt-free sex? What about the fact that marrying young is the No. 1 predictor of divorce?

The conversation is spreading from what pastors say is a relatively small number of churches and ministries that promote early marriage to the broader evangelical community, with the latest development being a Christianity Today magazine cover story this month titled "The Case for Young Marriage."

The article's author, University of Texas sociologist Mark Regnerus, argues that evangelicals "have made much ado about sex" but are damaging the institution of marriage by discouraging and delaying it.

Regnerus is not saying that premarital sex is OK. But he does suggest that abstinence has its limits, and that intensifying the message won't work. When people wait until their mid- to late 20s to marry, he writes, it's unrealistic and "battling our creator's reproductive designs" to expect them to wait that long for sex.

Statistics show that few Americans wait. More than 93 percent of adults 18 to 23 who are in romantic relationships are having sex, according to the National Longitudinal Study of Adolescent Health. For conservative Protestants in relationships and active in their faith, it's almost 80 percent.

Regnerus, a conservative Presbyterian, knocks the "abstinence industry" for perpetuating "a blissful myth" that great sex awaits just beyond the wedding reception. He advises against teen marriage, but argues that early 20s marriages are not as risky as advertised.

"I'll probably get framed as I want people to marry because I don't want them to have premarital sex," said Regnerus, author of "Forbidden Fruit: Sex and Religion in the Lives of American Teenagers."

"I think marriage is just a fantastic institution for people who think rightly about it, have realistic ideas about it and put the requisite work into it."

The median age for first marriages in the U.S. is about 26 for women and 28 for men, the highest figures since the Census Bureau began counting. Solid data on evangelicals is not readily available, but research suggests they marry only slightly younger, Regnerus said.

High-school sweethearts Megan and Jay Mkrtschjan planned to marry at 20. But the suburban Chicago couple waited an extra year to finish college under pressure from Megan's parents.

There were few doubts in their minds about marrying young. They had found each other. Why wait?

"For me, it was really a trust issue," Megan said. "Marrying right out of college was showing our friends, showing the people we were acquainted with, that we trusted our lives with God."

For Jay, a songwriter and guitarist, "the sex issue" was the best argument for early marriage. "By getting married young and dating for a shorter period of time, it leaves less room to sin sexually," he said.

Now four years married, the Mkrtschjans say their relative youth helped them through early trials, which at one point took them down to $26 in the checking account.

"We were going through these hardships together," said Megan, a fifth-grade teacher who owns a cake-decorating business. "It made things easier because we weren't stuck in our ways. We were open to what each other had to say."

Many young adults today view their 20s as a time for fun, travel, career-building or finding themselves -- not for settling down.

Among evangelicals, there's a tendency to wait because many believe God "is going to deliver me a spouse right to my door," so they don't actively seek one, said Glenn Stanton, director of family formation studies for the evangelical ministry Focus on the Family, a young marriage promoter.

Then there's what Stanton calls the "eHarmony philosophy" -- the belief God will deliver someone perfect.

Stanton doesn't blame the abstinence movement. "I don't think that it's so much to much focus on abstinence, but the silence on marriage makes the abstinence message sound so much louder," he said.

At Capitol Hill Baptist Church in Washington, D.C., associate pastor Michael Lawrence emphasizes that marriage is a covenant, not a convenient arrangement, and offers advice to young couples on overcoming arguments over money, sex and family.

"We probably haven't served our young people well by on the one hand emphasizing abstinence, but on the other hand telling them to wait to get married," Lawrence said. "It seems to be setting them up to fail."

Like most proponents of young marriage, Lawrence does not set an arbitrary "right" age for marriage. Waiting until after college might be advisable if the alternative is crushing debt or dropping out, he said.

Supporters of abstinence programs promote them as both marriage-preparation tools and longer-term support systems for those who don't marry.

Jimmy Hester, co-founder of True Love Waits, part of the Southern Baptist Convention's LifeWay Christian Resources, disagreed with the argument that abstinence past a certain age is too much to ask.

"There are too many examples of people who have done it," he said. "And not out of their own strength, even, but out of a relationship with God who gives them strength."

Johns Hopkins University sociologist Andrew Cherlin, who studies families and public policy, said young marriage is a tough sell. A half-century ago, when people married earlier, fewer people attended college, high school graduates could get good-paying factory jobs, women became mothers right after school and families were larger, he said.

"Most evangelicals, as well as most Americans, realize how expensive it is to raise children these days," Cherlin said. "The most important rationale for early marriage -- having a larger family -- has disappeared."

Some single evangelical women want to marry young, but the numbers are against them: single women outnumber single men in churches 3 to 2, and the available men are postponing growing up, Regnerus and others say.

Skeptics, meanwhile, suspect early marriage backers want to turn back the clock on gender roles.

"There is some rolling of the eyes, especially among women ... 'Why are you giving up your 20s and going back to the 1950s and June Cleaver?'" said Jay Thomas, college pastor at College Church in Wheaton, Ill.

Other evangelicals simply want to wait and cite their faith as motivation. Valerie Strattan, 24, of Chicago, has a serious boyfriend of 2 1/2 years. She believes that for now, God has called them to focus on separate pursuits: he's a musician, she works in refugee resettlement.

"We don't feel the rush to marry," Strattan said. "If I am listening to God, and he is listening to God, then God isn't going to lead us in separate places if he does truly want us to get married."

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