OK, so Dick says it comes from Mark Twain, and I usually believe Dick. I decided to do some digging and see where I ended up. Not much luck, I'm afraid. With several prettydamngood Web searches, all I came up with was this (click):

My Own Grandfather by Mark Twain After long years as a bachelor I was tired of being alone and married a widow with a grown daughter. My father fell in love with the daughter and took her as his wife. This made me my own son-in-law and my stepdaughter became my mother. After a year my wife gave birth to a son. Now, my son was my father's brother-in-law and at the same time my uncle, since he was my stepmother's brother. But my father's wife also gave birth to a son. So this was my brother and also my grandson, since he was the son of my daughter. This meant I'd married my grandmother, since she was the mother of my mother. As my wife's husband, I was also her grandson. And since the husband of a grandmother is always a grandfather, I am my own grandfather.

It sounds credible, but where's the documentation? If this is really a quote from Mark Twain, where was it published?

I can't say that this is Twain's text - but if Bill Foster says he saw a handwritten copy from 1829, I believe him. Bill is a very credible source.

-Joe Offer-