Now that my kids are both out of diapers, people ask me if we're thinking of having another.
To anyone thinking of asking anyone else that question, don't. Especially in casual conversation. Especially if you don't know the person all that well. Just don't do it. There are all kinds of piles that you might step in by asking that question and besides, it is rude. And none of your business.
You will know if we are having another kid when I tell you we're having another kid. Until then, we're enjoying the ones we have.
Let's go ahead and retire that question along with "Are you pregnant?", a question that should NEVER be asked. If you have to ask, you shouldn't.