No. They have few siblings and none of those few had children. There is one aunt I’ve never met that I don’t think married but I’m not 100% sure. So I have no known first cousins and probably no first cousins period.

In the west, family size is shrinking. My wife and I have dozens of first cousins each. Our children have exactly 12 first cousins, but their first cousins have anywhere from 9 to 18 first cousins. Our grandchildren currently have zero first cousins. Can you guess how many children we have? It...