Five years ago I made fun of Geni's twisted relationship finder that determined how William Shatner was 'related' to Leonard Nimoy.
A month ago, I uploaded portions of my family tree data to Geni, and have been playing with it for the past month. I still find what they term an "in-law relationship" to be rather silly at times. For example, Ruth Bader Ginsberg is my first cousin twice removed's wife's niece's husband's second cousin once removed. Can you follow that?
George Washington is my "fifth great uncle's great uncle's wife's niece's 2nd husband." Neither of these are as tortuous as Kirk and Spock's relationship above, though neither is a blood relationship. The George Washington connection goes through the ancestry of my fourth great grandmother, Sarah Showers Van Every. I have not confirmed all of the steps. I do know that I have a much less tortuous in-law relationship to our first President, but I didn't upload the data in my family tree for a cousin, so Geni doesn't tell me about it. George Washington's father is an ancestor of some first cousins, through one of his half-siblings.
If one can confirm ancestry to Colonial Americans, which I can, in a lot of cases connections to European royalty have been traced by others. Whether these connections are all accurate and truthful is open to question at times. As I did with Ancestry's discontinued We're Related App, I use the information it provides for my 'new' ancestors as a basis to research, and I essentially trust the ancestry done for the famous celebrities.
Geni makes it easy to search for the closest in-law and closest blood relationship paths of pretty much any public figure. (I do have a fourth cousin who is fairly well-known, but who isn't on the Geni website. I didn't upload his data to the site, and don't plan to. My second cousin twice removed, David "Jay and the Americans Black" Blatt isn't on the website either. As long as he is living, I won't be the one to enter his data, and if I did, I'd mark it as private.) I have discovered that I am 90th+ cousins with a few celebrities. How is that possible?
Well, those royal families had their ancestries traced back to the Bible. Some people trust those ancestries. So Abraham the Patriarch is my shared ancestor for a few. Intriguingly, Isaac is a great...great-uncle. I have not been able to trace my Jewish ancestral lines far enough back. And while I thought the Royals traced their ancestry back to King David, apparently my Royal ancestors did not, and their line to Abraham is through Ishmael. To connect with Isaac, a lot of Jewish lines go through Rashi. Rashi's Biblical descent is missing a few generations. 22 generations, traditionally. That's a lot of generations to skip, and trust, based on Tradition. Traditionally, my great grandfather was a Cohen, and thus a direct descendant of Aaron, Moses's brother. That's skipping a lot more generations, but the tradition is equally acceptable to my mind.
While seeing the connections to famous people still fascinates me at times, I hope to use the blood relationships it provides to actually help research/confirm some of my own ancestral lines a little further than I have.