Crazy But True, Genealogy Edition
John Tyler was the 10th President of the United States (and the first Vice President to be elevated to POTUS). He was born in 1790 and has 2 living grandchildren.
At the age of 63, Tyler's second wife gave birth to their son Lyon Gardiner Tyler. (The second Mrs. Tyler would give birth to two more children afterwards.)
Lyon Gardiner Tyler would have sons at the age of 71 and 75, respectively Lyon Gardiner Tyler Jr., born 1924, and Harrison Ruffin Tyler, born 1928.
And I thought it was hard enough to find someone living whose grandfather served in the Civil War.