15th Cousins? I have a few.

I recently posted a question on Facebook inviting people to make a guess.

"If two people share the same parents, they are siblings. If they share the same grandparents, they are 1st cousins. If they share the same great-grandparents, they are 2nd cousins. If we assume that everyone has 2 children, how many 15th cousins could I have?"

Unfortunately, no one offered a guess, but you could imagine there would be guesses ranging from 1,000 to 100,000. The correct answer is that I would have 32,768 15th cousins. To give you some prospective, there are about 34,000 people living in Butte, Montana.

Butte, Montana: Pop. =33,854 (2013)

Now, this is also in addition to the 16,384 14th cousins, 8,192 13th cousins, 4,096 12th cousins, 2,048 11th cousins, 1,024 10th cousins, 512 9th cousins, 256 8th cousins, 128 7th cousins, 64 6th cousins, 32 5th cousins, 16 4th cousins, 8 3rd cousins, 4 2nd cousins, 2 first cousins, 1 sibling and a partridge in a pear tree! If we add these all up (including myself) there would be a total of 65,536 living descendants of my 14th great-grandfather who was born around 1500 AD in Schweicheln, Germany. That's about the same as the population of Missoula, Montana. 

Missoula, Montana: Pop.=69,122 (2013)

Now, that would only be for my generation when in reality we would need to include my living nieces/nephew's generation, my parent's generation, my grandparent's generation, and even some of my great-grandparent's generation. This number of living descendants very well could be upwards of 100,000 which is about the population of the state of Montana. 

Montana, USA: Pop.=1,015,165 (2013)

Now, that's assuming that everyone had exactly 2 children who survived to adulthood and had 2 children of their own. In reality many descendants did not live to adulthood, marry, or have children. Many others had up to 12 children! To allow for comparison, if we assume that everyone had exactly 5 children, my 14th great-grandfather would have 30,517,578,125 descendants! That's a little over 4 times the current world population! 

Earth (x4): Pop.=7,276,626,200 (4:14 PM)
Pop. x 4 =29,106,504,800

Perhaps 2 is a better estimate of the average descendants per person on our family tree. 3 would give 14,348,907 (about the size of Illinois) and 4 would give 1,073,741,824 (about the size of India). 

So, why is any of this important? Because with numbers like these, there's bound to be other cousins out there who have done research on their little branch of the family which I could never have hoped to find out myself. I haven't yet determined how much of the family tree I will cover in my book. I've contemplated writing several volumes; one for every major branch since 1700 on my side of the family and have a similar chapter in each about the "ancient" Holzgrafe family from 1500-1700.