We only really know the answer to that after the fact. Even then, we only really know they aren't if they accidentally conceive and still regret it. It's not

We only really know the answer to that after the fact. Even then, we only really know they aren't if they accidentally conceive and still regret it. It's not uncommon to know someone who was childfree for years and years, only do a complete reversal when they have children late in life. That said, it's one of those topics of conversation where I might just say (to myself), "I hope you're right." To them I'd say, "oh, cool" and drop it. It's really nobody else's business.