How would you react if your child answers you back?

I guess Stan is right. There are times where children answer back but they really have a point. Sometimes it also depends on the culture within the family kaya sila may lakas ng loob to answer back. But if it's totally disrespectful already, he has to learn how to do it right next time.

My first impulse would be to be shocked and a little angry, but then we have to think that it's our job to discipline our children, whip them into shape, and make sure they grow up a kind and decent human being.

It depends. If my child has a valid point I'll take it. But if it's "pabalang", I'll talk to him or her with my wife for correction. P.S. I'll never hit my child.