Are all cousins created equally?
Do you think about how your cousins connect to your ancestors–not just how they connect to you?
One set of my great-great-grandparents has an oldest great-great-grandchild born in 1944 (not me). The youngest great-great-grandchild (I think) was born in 2006. That’s sixty two years and the oldest great-great-grandchild is old enough to be the grandparent of the youngest one. But the one born in 1944 and the one born in 2006 both have the probability of having the same amount of DNA of the great-great-grandparents they share. The age difference does not matter. It is the generational difference that matters.
If you’re thinking about having a cousin do a DNA test, think about one who is closer generationally to your common ancestor. It might not be a cousin who is close to you in age.
One response
I never knew that was the term for this phenomena. But, I became very aware of it soon after I started our family tree on Ancestry in 2012. Some articles focus on how the spread occurs with male ancestors who can have children late in life. I find the ones with female ancestors more interesting because of the limitations of when women can no longer get pregnant.
My paternal grandmother was born in 1894, when her mother was 21. Her younger sister was born in 1913, when my grandmother was 19 and their mother was 40.
My grandmother did not have her first until 1917 when she was already 23. Her sister had her last in 1948, when she was 35. The spread continues on from there. The child born in 1948 has very young grandchildren, all born after 2015 including one recently , who are 3rd cousins to children born in the 1970’s. Some of those born in the 1970’s are themselves already grandparents .
And it could have started out wider to begin with. My great-grandmother could have had her first when she was 18 and her last when she was 42. My grandmother could have had her first when she was 18 and her sister could have had her last when she was 42.
Interesting to think about.