A Family tree is something you pay a little to have looked up, and then pay more to have hushed up.
Definition.com
Dad Joke.com
What is the difference between a Genealogist and a Gynecologist?A Genealogist looks up your family tree, whereas a Gynecologist looks up your family bush
Definition.com
A Family tree is like riding in a train backwards: it shows you where you came from, but not where you're going.
Meme.com

Meme.com

Definition.com
The Family tree is a tree in which the branches are so uninteresting that they are forced to brag about the roots.
Meme.com

Definition.com
A Family tree is called what it is because if you look hard enough, you'll always find some sap in it.