Well, I know I've told this story before, but in this instance it is worth repeating.
An old man is sitting on a park bench when a punk rocker sat down next to him. Noticing the old man eyeing him up, the punker says, "What the he!! are you staring at, old man?"
The old man smiles and says, "I got drunk once and f*#&ed a parrot. I was just wondering if you are my son."