We are an atheist family in the Deep South, so that works out about as well as you'd expect. My family (not from the South) is quite religious as well. Like aquinas, I went through that twentysomething phase of diving deep into religion and history, but I came out at the other end (I was decidedly less impressed by Thomas Aquinas, for instance).
Yeah, it's definitely easier if you have clear beliefs. Over time my DD10 has learned to guard her beliefs in public, but she's very much interested in exploring this, so we send her along with her friend to church and summer retreats, she goes along, blends in, asks the occasional question, and then comes back to me for a different perspective. Since I'm pretty well versed, I can give her a multitude of different interpretations, but she tends to want to cut through all of that and get straight to mine.
It was just this past weekend where I delivered a defense of the Mosaic food prohibitions in a society ignorant of germ theory.
We did the whole Santa/Easter Bunny/Tooth Fairy thing, and having had that experience in an atheist family has done a wonderful service for teaching DD the perspective of believers. This is one of the primary reasons why she does not say things that her religious friends might find offensive.
As for how you might handle this sort of thing... have you considered exploring this together with your DS? Is it something you're actually interested in? If so, you could be reading adult-level literature, and sharing what you learn with him. If you're interested, I can recommend some resources via PM.
Also, I think this is an excellent answer that more people should apply more often: "I think this is probably the answer, but I could be wrong."
