This widow had a grown-up daughter Who had hair of red.
My father fell in love with her, And soon the two were wed.

This made my dad my son-in-law And changed my very life.
My daughter was my mother, For she was my father's wife.

To complicate the matters worse, Although it brought me joy.
I soon became the father Of a bouncing baby boy.

My little baby then became A brother-in-law to dad.
And so became my uncle, Though it made me very sad.

For if he was my uncle, Then that also made him brother
to the widow's grown-up daughter who, of course, was my step-mother.

Father's wife then had a son, Who kept them on the run.
And he became my grandson, For he was my daughter's son.

Who is my Grandpa?