Son takes his father to the doctor. Doctor gives them the bad news
that the father is dying of cancer. Father tells the son that he has
had a good long life and wants to stop at the bar on the way home to
celebrate it.

While at the bar, the father sees several of his friends. He tells
them that he is dying of AIDS.

When the friends leave the son asks, "Dad, you are dying of cancer.
Why did you tell them that you are dying of AIDS?"

The father replies, "I don't want them fucking your mother after I'm
gone!"