I grew up in a nonreligious household in what was even then a notably irreligious part of the country (an hour north of Boston in New Hampshire). Dad had gone to Catholic school in the Midwest but never bought the scheme; Mom had gone to some nondenominational Protestant church as a matter of social course and was told little more than “Don’t wear make-up and short skirts.” There was no Internet, all of my churchgoing friends were Catholic, and discussions of theology among friends and family members were just not a part of my life. I did understand that atheists were a much-tsk-tsked bunch of people, but this was mostly an abstraction.On the whole I would say I was a nonbeliever in the chiefly atheistic sense, normatively speaking, from the start — I even remember asking my dad when I was around seven, “Why do people believe in God?” and not “Who or what is God?” and the way I phrased this alone was probably indicative of where I would wind up on the belief scale. (As I recall, his answer was along the lines of, “Because they were mostly slaves who worked all day for a bucket of soup and needed something better to believe in than that.”)
I would say that the moment I rejected God, at least textual version of it, was when I read Genesis in detail for the first time. I was around 18 and had already taken science courses involving evolution and geology and was a pronounced astronomy buff (and still am). I remember thinking, perhaps even out loud, “This is a bunch of fucking horseshit! How can anyone believe a word of this?” And this was in 1988 or so, long before the advent of the Web and its attendant “culture wars” and everything they entailed and continue to entail.
I can’t be alone in being definitively turned away from religious belief by a brief but vital exposure to the very instrument most often used to promote that belief.