We've heard colleagues referring to people with "Guts", or with "Balls".
Do they know the difference between them?
Here's the official distinction; straight from the British Medical Journal: Volume 323; page 295
GUTS: is arriving home late, after a night out with the lads, being met 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 lads, smelling of perfume and beer, lipstick on your collar, slapping your wife on the bum and having the "Balls" to say: "You're next, Chubby".
I trust this clears up any confusion.
Medically speaking, thee is no difference in outcome; both are fatal.