No, this is not a Kentucky joke, and yes, I have provide the lyrics of “I’m my Own Grandpa” at the bottom.

But this is the explanation, according to the article.

“The answer to that medical mystery, sparked by a confusing paternity test result, is “When the genes of a vanished twin brother live on in the mother’s DNA.” The finding, which genetics experts reported earlier this month, suggests that such human “chimeras” — people with DNA from more than one embryo — could be more common than we thought.”

The article in interesting, this is stuff that I never knew could happen.

DNA showed a mother was also her daughter’s uncle — how scientists solved this medical mystery – Why you may have more aunts and uncles than you suspected at the holiday table.

Now, many many years ago
When I was twenty three
I was married to a widow
Who was pretty as could be

This widow had a grown-up daughter
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
‘Cause she was my father’s wife

To complicate the matters
Even though 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
That also made him the brother
Of the widow’s grown-up daughter
Who, of course, was my step-mother

I’m my own grandpa
I’m my own grandpa
It sounds funny I know
But it really is so
I’m my own grandpa

My father’s wife then had a son
That kept them on the run
And he became my grandchild
For he was my daughter’s son

My wife is now my mother’s mother
And it makes me blue
Because, she is my wife
She’s my grandmother too

I’m my own grandpa
I’m my own grandpa
It sounds funny I know
But it really is so
I’m my own grandpa

Now, if my wife is my grandmother
Then, I am her grandchild
And every time I think of it
It nearly drives me wild

For now I have become
The strangest case you ever saw
As husband of my grandmother
I am my own grandpa

I’m my own grandpa
I’m my own grandpa
It sounds funny I know
But it really is so
I’m my own grandpa

I’m my own grandpa
I’m my own grandpa
It sounds funny I know
But it really is so
I’m my own grandpa