with questions of living with a lot of different faith groups in their schools and network of friends. they're inundated with media, with different perspectives. >> author david kinman has studied this phenomenon. 8 million millennials give up on god by their 30th birthdays. >> 59% of people who grow up in a christian home are going to walk away on some level. they're either going to become ex-christians or dechurched. ♪ >> david gormley struggled for years and at 16, gave up on god. >> i actually came out as an atheist. i didn't want to lie to people anymore. i was just tired of pretending that i was someone that i wasn't. >> david's news rocked his deeply faithful family. do you remember how they took it? >> with quiet silence at first. for about six months afterwards,