What bothers me about this is that people, naturally wanting to "avoid the discussion" about a decision to not have kids, are talking creative ways to beandip around the actuality of the situation. I get it, because it can be awkward, but I think what really needs to be addressed is the assumption people make that they are in any way entitled to question that decision. It's OKAY to say you don't want kids. It's not okay for people to act as if that's some awful/unheard-of idea.
"Oh, no kids, c'mon, you'll change your mind..."
"It's not actually up for debate."
I can see both sides. That is, I can see why an individual might not want to get into a discussion about not having kids; and I can also see how another individual, with the same proclivities, might want to take a stand that bean dip is not necessary and people's assumptions should
be shot down. I think either approach is valid if done politely.
Instead of "kids" I started substituting "dogs" into the comments. Like, "Your new house has such a huge backyard! That'll be great for the dogs to run around in." I would immediately be like, "Dogs? What dogs? We don't have dogs." If they said, "Oh, well, surely you'll be getting some soon..." that would really become absurd and I would have no problem saying, "Uh, no, we're not really into dogs, actually." While making a mental note to interrogate my SO--"You haven't been telling people we're getting a dog, have you?!"
Also I see a difference between a pleasant, assuming comment and anything that reeks of persuasion or argument. "Oh, that house is in a great school district, that's wonderful for your future kids," is, to me, easier just to deflect. But something like, "When are you having kids? Time's running out, you know! Don't you want to give your parents grandchildren?" to me at least is worthy of being shut down a bit more abruptly. "That's not really something I discuss with people" perhaps.
And what PastryGoddess said.