"When are you going to start having kids?"
It's a question I've been asked different variations of since I was a high school senior. It started with "You'll be wanting to get married soon and start a family!" to "You're not getting any younger, and you're going to want to have energy to keep up with your kids! You'd better get married soon!" which progressed to "When are you getting married? You won't find one better than him!" (I did) to simply "When are you going to start having kids?"
I do get this one less and less frequently now that I'm getting older, so perhaps, after months of nobody asking, I was finally prepared with an answer this morning when a woman I barely know essentially told me I'd better start having children because I was going to be too old soon and I'd regret it.
My response? (After the initial internal "...Wow." I mean?)
"I'm not planning on having children because I'm afraid my enemies would try to use them as leverage."
That one, ladies, is a keeper. Take note of it. I've never seen a nosy woman back off so quickly and silently!