I’m an atheist because I was born that way.
My parents were not church-goers, but I was christened in the local Church of England, because that’s what my family did. My mother, in particular, was quite happy for me to be given enough information about the church to “make up my own mind”. When I was old enough, I went to Sunday School. I don’t remember particularly liking it or disliking it, but I didn’t have to go too many times before my parents let me stop.
I remember being given a illustrated book of Bible stories when I was about 8 or 9. I liked the stories, and read them a few times. But all the time, I had this feeling that said: “But it’s not true. It’s just made up. Why would people believe in this?”
When I got to be a teenager, I had a small Pascal-style crisis of faith (not that I had heard of Pascal, of course). I wondered to myself about what would happen if I was wrong. If there was a God, and I did not worship Him, I would go to hell. Hell was pretty scary. So I considered going to church and going through all the right motions. But I couldn’t. I figured that I just plain didn’t believe, and if a God existed, he would see through any pretend worship. So I decided to just go ahead living without God – because what else could I do?
I worried less and less about it, but it took me until my early twenties until I finally got rid of the last vestiges of doubt. That happened when I was speaking with an atheist guy I worked with about life after death. He brought up the topic of religious belief in the afterlife, and I jokingly said something about “just in case they’re right”. He looked at me and said, “No – they’re wrong.”
Something clicked when he said that, and I realised that of course “they” are wrong and “we” are right.
Now, I can back up my feelings with all sorts of logic and rationality, and lots of information that I have learned at Pharyngula and through the writing of Dawkins, Hitchens and so on. But I still think that I was just plain born as a non-believer.