Sunday, January 23, 2011

Oh Dear....My Son is My Cousin

One of the curiosities of genealogy is that, as you go back in time, the world population decreases even as the number of your own ancestors increases. For example,  you have
  • 2 grandparents
  • 4 great-grandparents
  • 8 2nd-great-grandparents
  • 16 3rd-great-grandparents
  • 32 4th-great-grandparents
and so on with each generation adding twice as many ancestors as the prior generation. At some point, you will have more ancestors than are represented in the entire world population!

A recent article in Family Tree Magazine discussed this phenomena called "pedigree collapse." It happens to the best of us.

Here's a video from YouTube which presents a hypothetical (and hilarious!) example:

Now that you've wiped the tears of laughter from your eyes, let's look at the only example I've found in our family tree (so far....I'm sure there are more).

My son's father is a descendant of Abraham and Mary Eaton through their son William; I am a descendant of the same couple through their son Absolem. As a result, my ex-husband is my fifth cousin, making my son my fifth cousin once removed, and my grandchildren my fifth cousins twice removed! Freaky!

© 2011 Denise Spurlock


  1. Thanks for the morning laugh! yes, it is freaky. LOL.

  2. Denise that is hilarious and I think it I have some similar cases in my own family. Very funny thank you!