One of my coworkers who is my age (31) asked me in conversation if I had kids. I'm childfree (had a tubal at 25) but didn't mention that, so I just said "nope" because really, I figure the more neutral the response the less likely someone is to press on as to why.
She has three kids of her own, the oldest being in middle school. Her response? "Lucky you!".
I was tempted to make a snarky reply along the lines of "yeah, well, I figured out a long time ago that they're preventable", but instead I just bean-dipped into a conversation about my cats. It occurred to me later though: what if I'd been infertile or TTC and having difficulty? Would there have been anything even remotely E-Hell appropriate to say in response?