I wasn't raised explicitly atheist--that is to say, when I was young, no one told me, "God does not exist." (Though I could conceivably have overheard it when someone wasn't talking to me.) But I was also certainly not raised theist. And I was taught (via very aggravating, though now I recognize also useful, conversations with my dad) to have good arguments. If I said, "So, everyone X, right?" as the beginning to an argument, he'd say, "Oh? Why do you say that?"