It's amazing to think that someone born in 1790 could have grandchildren still alive today.

From 1790 when President Tyler was born to the present, 2014, where two of his grandchildren are still alive.

I remember several years ago, C-SPAN did a special series on the presidents' children and they interviewed descendants of various presidents. One of them was John Tyler's grandson.

" Chester Alan Arthur III, was a San Francisco astrologer and sexologist and a grandson of U.S. President Chester A. Arthur."

http://en.wikipedia.org/wiki/Gavin_Arthur

Of course, there's the controversial matter of Elizabeth Ann Blaesing, daughter of the author of "The President's Daughter," Nan Britton, whose claim that Elizabeth was conceived in the White House with President Harding. At any rate, Elizabeth died only ten years ago terminating the direct line from Harding.