One of the issues that often comes up when I report data which show that the young are more secular (or liberal) than the old is that people change with time. And age is presumed to correlate with greater religiosity and conservatism. I'll take politics off the table. The Inductivist suggests that the GSS doesn't indicate that the young become anymore religious with age. In other words, religiosity at age X is a very good predictor of religiosity at age X + n. Christian Fundamentalist pollster George Barna observes the same in his surveys:
The research data showed that one pattern emerged loud and clear: young adults rarely possess a biblical worldview. The current study found that less than one-half of one percent of adults in the Mosaic generation - i.e., those aged 18 to 23 - have a biblical worldview, compared to about one out of every nine older adults.
Earlier Barna reported:
One of the most fascinating insights from the research is the increasing size of the no-faith segment with each successive generation. The proportion of atheists and agnostics increases from 6% of Elders (ages 61+) and 9% of Boomers (ages 42-60), to 14% of Busters (23-41) and 19% of adult Mosaics (18-22). When adjusted for age and compared to 15 years ago, each generation has changed surprisingly little over the past decade and a half. Each new generation entered adulthood with a certain degree of secular fervor, which appears to stay relatively constant within that generation over time. This contradicts the popular notion that such generational differences are simply a product of people becoming more faith-oriented as they age.
Conservative Christians do have more children than the young, but the atheist childless seem awful good at seducing the souls of the innocent.