This commentary in the Los Angeles Times suggests that young people are being turned off by churches that seem to embrace conservative politics:
The most rapidly growing religious category today is composed of those Americans who say they have no religious affiliation. While middle-aged and older Americans continue to embrace organized religion, rapidly increasing numbers of young people are rejecting it.
As recently as 1990, all but 7% of Americans claimed a religious affiliation, a figure that had held constant for decades. Today, 17% of Americans say they have no religion, and these new “nones” are very heavily concentrated among Americans who have come of age since 1990. Between 25% and 30% of twentysomethings today say they have no religious affiliation — roughly four times higher than in any previous generation.
So, why this sudden jump in youthful disaffection from organized religion? The surprising answer, according to a mounting body of evidence, is politics. Very few of these new “nones” actually call themselves atheists, and many have rather conventional beliefs about God and theology. But they have been alienated from organized religion by its increasingly conservative politics.