The Difference Between A Father and A Dad

The other night, I was listening to the song, "Androgynous" by The Replacements, and encountered an intriguing lyric:

"Don't get him wrong.

Don't get him mad.

He might be a father, but he sure ain't a dad."

It got me thinking. What's the difference between a father and a Dad?

I've always used the terms synonymously, but Paul Westerberg (the writer of the aforementioned lyric) jarred me. And the more I thought about it, the more I realized; there is a difference. 

A father is a biological phenomenon. A male who provides the seed that leads to the creation of a new life. Fatherhood has nothing to do with ethics, morality or even species. Sociopaths and assholes can be fathers. Ditto dogs.

A Dad, on the other hand, is a male who helps raise a child (whether he is the biological father, or not). A Dad is present. A Dad is engaged. A Dad shows up, and gives a shit. Being a father is a condition. Being a Dad is a commitment.  

In other words, all Dads are fathers, but not all fathers are Dads.