The Secular Student Alliance, a national organization for the secular student movement, reports that the number of atheist or agnostic student groups on U.S. campuses has more than doubled over the past two years from 80 to 162, according to a recent story from Religion News Service.

In the article, outspoken atheist PZ Myers, who teaches biology at the University of Minnesota, points to popular books (such as Christopher Hitchens’ God is Not Great and Richard Dawkins’ The God Delusion) as “saying that it is okay to be ‘godless.’”

Most of the SSA affiliate groups are on college campuses — although four are in high schools. Lyz Liddell, who organizes the campus groups, told RNS that college is the time when beliefs are questioned and young people often break away from their familiar religious backgrounds.

She also noted that social networking sites — like Facebook — have given students and others a forum for processing a change in belief — often anonymously.

What challenges come from a more aggressive presentation of unbelief that creates community and takes on a positive, public face? It is a question church educators, student ministers, Christian parents and all other alert believers cannot afford to ignore.

Historically, only a very few Americans have self-identified as not believing in God. Though still numerically small, the increasingly public face of atheism — through popular books, social networking and student organizations — may boost those numbers.

Finding reasons to not believe takes little effort: bad theology, obnoxious believers, conflicting biblical texts, religiously justified abuse, and inconsistencies between the words and deeds of those professing faith.

Of course, stated belief and related behavior are often compartmentalized — in that some of the worse atrocities have come from the hands of those claiming to believe in God and often professing divine cause for their behavior. Such realities place a large checkmark on the side of those making the case against belief in God.

In my many years on college and university campuses (as a student and then a campus minister) it was rare to hear someone outright state a belief that God does not (or probably does not) exist. Usually the struggles were healthy — though at times painful — destructions of belief systems that needed to be rebuilt on better theology and practice.

Others moved away from their childhood faith traditions more significantly, but still seemed focused on finding a different way to understand and acknowledge the divine.

“I tried Christianity for awhile and it didn’t work for me,” one student told me. But I could tell that his search was continuing. He wanted to come back and talk some more.

The route from belief to unbelief often travels the road that theologians have long called “the problem of evil:” How could a loving God let such horrible things happen?

In his book, Reasons to Believe: One Man’s Journey Among the Evangelicals and the Faith He Left Behind, John Marks (a producer for CBS’ 60 Minutes) kindly gives his reasons not to believe. He too ends up at the troublesome place for both believers and nonbelievers.

“A god who can’t stop it has no right to my loyalty or belief … Leave me behind,” he writes in conclusion. The “it” referenced by Marks is the incredible suffering of the Holocaust, Rwanda and other atrocities of great proportion.

Our response to a growing (or more public airing of) unbelief cannot be shallow attempts to answer such unanswerable questions or defensiveness when they are raised. Doubt plays such a significant role in faith that to suggest these very questions do not trouble us as well is both counterproductive and dishonest.

In all of our current debates over Calvinism, theories of biblical interpretation and mission methodologies, we might need to give more attention to basics of belief in God. And it must be done carefully, thoughtfully and compassionately.

Dismissing doubters or atheists as nuts or evildoers is wrong on more than one level. According to the RNS story, the Students for Freethought at Ohio State University joined with the Coalition for Christian Outreach in spending their spring break doing community service in New Orleans.

And it may well be that unbelief is carving out space as a position of intellectual superiority.

For some Christians (and other theists), the case for belief can be argued intellectually and perhaps even convincingly. For most, however, the best case is made by professing that Jesus is Lord — and then acting like it.