I read a report once that said that spirituality is influenced by our genes. In the study, they found that something like 90% of those who had this gene were religious, while like 85% of those who didn't were athiest. And the number of people without it are growing.
I think the report said something about reaching the point where we're starting to evolve beyond the need for religion, so the gene is going dormant or something. I'll see if I can find it.
EDIT: http://www.time.com/time/magazine/article/...-725072,00.html
Haven't re-read it yet so I dunno how much of what I remembered is accurate.
EDIT2: Ha, what I remembered seems to be completely inaccurate.