I'm not hugely vocal IRL about being childfree, but I've been pretty lucky with those I've told. I've definitely had a few surprised faces/comments, but nothing I can recall in the questioning/denial range.

That said I've not told my family, and they can be very traditional in their views, so I'm pretty sure they think at some point I'm going to up and find a man to marry and provide them with at least one grandchild/[insert other appropriate name for my offspring here]. In reality it's possible none of those things will be true.

What I tend to find irritating at the moment is the automatic assumption that I want children. Or in one special case, that I already have children.