h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

How many of them were related?

Not in the sense that Bush and Son are, but which preseidents have family roots in common?

A study for the apt pupil, I feel.

Good point I forgot that.

The Adams' were also father and Son.
The Roosevelts were cousins of some seperation I believe.

I knew I forgot something out.

Hilary of course may become the first former First Lady to be related to another President.

George W. Bush (the 43rd president) is the son of George Bush (the 41st president).

John Quincy Adams (the 6th president) was the son of John Adams (the 2nd president).

Benjamin Harrison (the 23rd president) was the grandson of William Henry Harrison (the 9th president).

James Madison (the 4th president) and Zachary Taylor (the 12th president) were second cousins.

Franklin Delano Roosevelt (the 32nd president) was a fifth cousin of Theodore Roosevelt (the 26th president). Genealogists have determined that FDR was distantly related to a total of 11 U.S. presidents, 5 by blood and 6 by marriage: John Adams, John Quincy Adams, Ulysses Grant, William Henry Harrison, Benjamin Harrison, James Madison, Theodore Roosevelt, William Taft, Zachary Taylor, Martin Van Buren, and George Washington.

There's more than this. I read somewhere - and I'll need to do more digging to confirm this - that a large number of presidents have come from a very small number of families, and that some of those families are related by marriage, providing America with a sort of "royal family"...