I found this clipping. I am not sure of the source. It could be a Family Weekly from long ago.

ALL IN THE FAMILY

Everybody comes from 2 parents, 4 grandparents, 8 great-grandparents, 16 great-great-great-grandparents, etc.  Every generation back we go, we have twice as many lineal ancestors.

This is very much like the Persian Chessboard problem. If there are, say, 25 years to a generation, then 64 generations is 62×25=1600 years ago, or just before the fall of the Roman Empire. So, everyone of us alive today had in the year 400 some 18.5 quintillion ancestors or so it seems to say nothing about collateral relatives.

But this is far more than the population on the Earth, then or now. It is far more than the number of human beings who ever lived. Something is wrong with our calculation. What? We have assumed all those lineal ancestry to be different people. But this is not the case. The same distant ancestry is related to us by many different routes. We are repeatedly connected with our relatives. Every marriage bring cousins together.

If we go back far enough, any two people anywhere on Earth HAVE A COMMON ANCESTOR. Whenever a new American President is elected, someone generally in England dissevers that new President is a distant relative of the Queen of England. This announcement is intended, perhaps, to soothe any residual American longing for a king of our own. Of course, when two people derive from the same small corner of the world, and their genealogies are well-recorded, the last common ancestor can be discovered. But whether is can be discovered or not, a relationship is clear: WE ALL ARE COUSINS- all members of a vast world-girdling family.

SHOULD WE HAVE A REUNION??????