If you really want to see a surprised look, tell someone you don't want grandchildren. My don lives 8 hours away from me. Even if he decides to have children i wouldn't see them often enough to love them.

Ignore them. You are your own person. You are not required to be friends with or think like your co workers. Avoid them & the topic unless you are ready for the conflict.

None of that is anyone else's business and your co-workers were seriously out of line. It's your personal life and they are being incredibly inappropriate by even bringing those topics up at work. I'd keep looking for another job.

There are many things that we can change and more things we can't change...But always we can change our attitude!!

You need to join a union.

These things can be classed as discrimination. You don't have to tolerate it.

If you tell them you don't have any children, they ask what is wrong with you (physically).
I just tell them I'm shooting blanks, then I walk away.

It can be difficult to separate one's personal life from work. That's what I try to do.

I discuss weather and kittens at work

Just use behaviorist techniques to train the bores to stick to upbeat subjects. Works quickly.

Pay no attention to, or even look at, people whenever they are talking religion or being nosy; just act bored, nod distractedly, murmur "Um-hum" patronizingly, glance at your watch, excuse yourself and LEAVE.

Repeat until you have trained them to behave around you. People can stand anything except to be ignored.

This is ridiculous as it has no bearing on your ability to perform your job duties. I would be looking for a better job!