which pointed out, among other things, that if you go back 10 generations you have 4100 10x-great grandparents, and literally thousands of cousins. Also a fun fact: 80% of the marriages throughout history were between second cousins, as the population was smaller prior to the Renaissance. A child born in England in the 1200s was related to 75% of the population of the country. People who can trace their ancestry back to the 1500s often find they are descended from the same relatively small group of people.

My dad was born in rural NC in the 1930s and has "double first cousins." One of his father's sisters married one of his mother's brothers, and both couples had kids, therefore he and the other couple's kids are double first cousins. Not uncommon back when the population of an area consisted of a few large families and people didn't travel or move much.

Yes, this explains Roy Clark but maybe not Cindy Crawford.