This is a very tricky question. Ive blogged about it before. It really depends on a few things:
-how I am feeling
-where I am
-how well I know the person
You would be surprised how a simple answer can steer the whole conversation. You would think that a simple reply of "3 kids" would be easy and they would just leave it at that. Nope, not so much. Ive been asked a ton of questions after I reply with 3. Ive been asked how old they are and even where they are right now and what they are doing. Seriously, how do I reply to that. So it all depends how much I'm willing to get into at the time.