"We are very cognizant that this does not mean there's been a straight-up spike in nonbelievers, " said Paul Fidalgo, communications director for the Center for Inquiry, a secular advocacy group.

CNN: Millennials leaving church in droves, study says

It's also good news for strict church-state separationists, Fidalgo said, especially those who want to see traditional religious morality disappear from debates over women's health, abortion, same-sex marriage and climate change.

CNN: Millennials leaving church in droves, study says