Welp, I got the question tonight. The unvarnished, unadorned, completely straightforward, no wiggle-room question: But how do the mommies and daddies make the babies?
I need some time to consider how much information to give him, and in what way, so I dodged a bit. Fortunately, it was bedtime, so I did what I always do when he asks a question just before bed. I told him we'd look it up and discuss it the next day. I've heard some good things about certain books, which will at least help provide a framework for the explanation.
This topic doesn't freak me out, and I've made a practice of being somewhat matter-of-fact about these types of questions. What bums me out the most about this landmark is that I know he won't be able to keep this fascinating new information to himself. I can look forward to him discussing the nitty-gritty of baby-making with his classmates, teachers, my mother and the server at the next restaurant we patronize.
And then I'll have to tell him that's not a topic for public discussion, and then -- no pun intended here -- the seed has been planted. Sex is something mysterious and dark that freaks people out, just like death. (No honey, it's not really nice to tell your grandfather you thought most people died before they got to be as old as he is. I know he laughed. But really.)
Plus, my baby is growing up. Maybe that's what really tugs at me.