(Please see Corrections & Amplifications item below.)

'How can we stop the oil gusher?" may have been the question of the summer for most Americans. Yet for many evangelical pastors and leaders, the leaking well is nothing compared to the threat posed by an ongoing gusher of a different sort: Young people pouring out of their churches, never to return.

As a 27-year-old evangelical myself, I understand the concern. My peers, many of whom grew up in the church, are losing interest in the Christian establishment.

Recent statistics have shown an increasing exodus of young people from churches, especially after they leave home and live on their own. In a 2007 study, Lifeway Research determined that 70% of young Protestant adults between 18-22 stop attending church regularly.

Statistics like these have created something of a mania in recent years, as baby-boomer evangelical leaders frantically assess what they have done wrong (why didn't megachurches work to attract youth in the long term?) and scramble to figure out a plan to keep young members engaged in the life of the church.

Increasingly, the "plan" has taken the form of a total image overhaul, where efforts are made to rebrand Christianity as hip, countercultural, relevant. As a result, in the early 2000s, we got something called "the emerging church"—a sort of postmodern stab at an evangelical reform movement. Perhaps because it was too "let's rethink everything" radical, it fizzled quickly. But the impulse behind it—to rehabilitate Christianity's image and make it "cool"—remains.

There are various ways that churches attempt to be cool. For some, it means trying to seem more culturally savvy. The pastor quotes Stephen Colbert or references Lady Gaga during his sermon, or a church sponsors a screening of the R-rated "No Country For Old Men." For others, the emphasis is on looking cool, perhaps by giving the pastor a metrosexual makeover, with skinny jeans and an $80 haircut, or by insisting on trendy eco-friendly paper and helvetica-only fonts on all printed materials. Then there is the option of holding a worship service in a bar or nightclub (as is the case for L.A.'s Mosaic church, whose downtown location meets at a nightspot called Club Mayan).

"Wannabe cool" Christianity also manifests itself as an obsession with being on the technological cutting edge. Churches like Central Christian in Las Vegas and Liquid Church in New Brunswick, N.J., for example, have online church services where people can have a worship experience at an "iCampus." Many other churches now encourage texting, Twitter and iPhone interaction with the pastor during their services.

But one of the most popular—and arguably most unseemly—methods of making Christianity hip is to make it shocking. What better way to appeal to younger generations than to push the envelope and go where no fundamentalist has gone before?

Sex is a popular shock tactic. Evangelical-authored books like "Sex God" (by Rob Bell) and "Real Sex" (by Lauren Winner) are par for the course these days. At the same time, many churches are ﬁnding creative ways to use sex-themed marketing gimmicks to lure people into church.

Oak Leaf Church in Cartersville, Georgia, created a website called yourgreatsexlife.com to pique the interest of young seekers. Flamingo Road Church in Florida created an online, anonymous confessional (IveScrewedUp.com), and had a web series called MyNakedPastor.com, which featured a 24/7 webcam showing five weeks in the life of the pastor, Troy Gramling. Then there is Mark Driscoll at Seattle's Mars Hill Church—who posts Q&A videos online, from services where he answers questions from people in church, on topics such as "Biblical Oral Sex" and "Pleasuring Your Spouse."

But are these gimmicks really going to bring young people back to church? Is this what people really come to church for? Maybe sex sermons and indie- rock worship music do help in getting people in the door, and maybe even in winning new converts. But what sort of Christianity are they being converted to?

In his book, "The Courage to Be Protestant," David Wells writes:"The born-again, marketing church has calculated that unless it makes deep, serious cultural adaptations, it will go out of business, especially with the younger generations. What it has not considered carefully enough is that it may well be putting itself out of business with God.

"And the further irony," he adds, "is that the younger generations who are less impressed by whiz-bang technology, who often see through what is slick and glitzy, and who have been on the receiving end of enough marketing to nauseate them, are as likely to walk away from these oh-so-relevant churches as to walk into them."

If the evangelical Christian leadership thinks that "cool Christianity" is a sustainable path forward, they are severely mistaken. As a twentysomething, I can say with confidence that when it comes to church, we don't want cool as much as we want real.

If we are interested in Christianity in any sort of serious way, it is not because it's easy or trendy or popular. It's because Jesus himself is appealing, and what he says rings true. It's because the world we inhabit is utterly phony, ephemeral, narcissistic, image-obsessed and sex-drenched—and we want an alternative. It's not because we want more of the same.

Corrections & Amplifications

Pastor Mark Driscoll at Seattle's Mars Hill Church has talked about sexual topics in church services but says he has not delivered sermons with sex-themed titles. An earlier version of this column mistakenly used the word sermon.

Mr. McCracken's book, "Hipster Christianity: Where Church and Cool Collide" (Baker Books) was published this month.