One of Charlie's friends at daycare has two mommies, as does one of his best friends down the street. It's really interesting to see how this doesn't strike Charlie as worth noting in any way.
It's great because the natural diversity of our neighborhood creates lots of teachable moments to casually mention to him that sometimes kids have two mommies (or daddies). We haven't had that convo yet... but now that I think about it, I'll make it a point to talk casually with him about how sometimes kids have two mommies (like his friends at daycare and down the street) and that it's not a big deal.
Do any of your LO's friends (or your LO) have two moms or dads? Have you talked to your LO about gay marriage?