"Family tree" joke

A boy was assigned a paper on childbirth and asked his parents "how was I
born?" "Well honey..." said the slightly prudish parent, "the stork brought you
to us."
"OH," said the boy. "Well, how did you and daddy get born?" he asked.
"Oh, the stork brought us too."
"Well how were grandpa and grandma born?" he
persisted.
"Well darling, the stork brought them too!" said the parent, by
now starting to squirm a little in the Lazy Boy recliner.
Several days later, the boy handed in his paper to the teacher who read with
confusion the opening sentence: "This report has been very difficult to write
due to the fact that there hasn't been a natural childbirth in my family for
three generations."
-told by the minister of my church, Dr. James Kennedy,
Coral Ridge Presbyterian, Ft. Lauderdale.