Do you have guts or balls?

A medical definition of these was sent to me by an MD. The difference
between "guts" and "balls"...

Guts - is arriving home late after a
night out with the guys, being assaulted by your wife with a broom, and
having the guts to ask: "Are you still cleaning, or are you flying
somewhere?"

Balls - is coming home late after a night out with the guys, smelling
of perfume and beer, lipstick on your collar, slapping your wife on the
ass and having the balls to say, "You're next.