I'm My Own Grandpa

It's many, many years ago
 When I was twenty-three
 I was married to a widow
 Who was pretty as can be
 This widow had a grown-up daughter
 Who's hair was red
 My father fell in love with her
 And soon these two were wed
 This made dad my son-in-law
 And changed my very life
 My daughter was my mother
 'Cause she was my father's wife
 To complicate the situation
 Though it brought me joy
 I soon became the father
 Of a bouncing baby boy
 This little baby then became
 A brother-in-law to Dad
 That made him my uncle
 Though it made me kinda sad
 Cause if he was my uncle
 Then he also was a brother
 To the widow's grown-up daughter
 Who of course was my step-mother
 My father's wife then had a son
 Who kept him on the run
 He became my grandchild
 Because he was my daughter's son
 My wife is now my mother's mother
 And that makes me blue
 Because although she is my wife
 She's my grandmother too
 And if my wife is my grandmother
 Then I'm her grandchild
 And every time I think of that
 It nearly drives me wild
 Now I have become
 The strangest case you ever saw
 As husband to my grandmother
 I am my own grandpa
 Well I'm my own grandpa
 I'm my own grandpa
 That may sound funny I know
 But it really is so
 I'm my own grandpa