Some of these are pretty good. Having a large family and getting this question all the time, especially during the holidays, I may try a few. Although, the humor may be lost on the older members of my family, everyone else will probably enjoy them.

A similar joke/response to the question:
Why don't you have any children?
I DID....but I had to give them away, the cat was allergic to them.

ROFL, blame it on the cat...

Thanks for the clip by the way... not that I need it, but it was fun to read
*frantically putting more paper into printer*