If you’ve ever taken a course in probability, you’ve undoubtedly learned to mathematically prove the Birthday Problem: if you gather a relatively small number of people in a room, the likelihood that two will have the same birthday is much higher than seems possible without the “proof.” (With just 23 random people in a room, there’s a 50% probability that two of them will have the same birthday!) See the Wikipedia explanation of this phenomenon (if you care) at The Birthday Problem.
But what’s the probability that my dad and his g-g-grandfather would have the same birthday? That’s four men of direct lineage (dad, grandfather, great grandfather, g-g grandfather). We’re not talking uncles or great aunts — but directly back through his dad’s side to the guy who started the Gartz (originally Görz) lineage in my grandfather’s home town.
I won’t do the math, but it seems to me a long shot — sometimes called an amazing coincidence! So I’ll just say HAPPY BIRTHDAY TO my G-G-G Grandpa, Johannes Michael Görz, born OCTOBER 10, 1769 (no photo obviously, but here’s his birth registration from Gerstheim, Alsace, before his Dad up and took the whole family (little Johann was just eight months old on this 1,000 mile trek) to Hungary, now Romania.
See Unraveling the Michael Mystery for details on discovering of this 242-year-old document.
And Happy Birthday, Dad: October 10, 1914 (he’d be 97), born 145 years after Johannes Michael.