(Today's Tip of the Day had me thinking about this.) Not a single person here has asked us about kids. About whether or not we already have them. About whether or not we plan to have them. Nothing.
If we had just moved to a new place in the States, I'm pretty certain that the "Where are you from?" question would be immediately followed by "So, do you have kids?"
And it's not that I even mind being asked the question. (I used to mind it, but not anymore.) It's a pretty natural thing to ask. I just think it's an interesting cultural difference.