A doctor is walking down the street...

...and he passes a man with a head the size of a golf ball. Before he can stop himself he yells "sir!"

The man turns around, and the doctor says "I'm sorry to bother you, but as a physician, I've never seen a condition like yours. How do you have a head so small?"

The man says "Well, it's funny you ask. I was walking down the beach one day when a bottle happened to wash up on the shore. I picked it up and a genie came out in the form of a beautiful woman! She told me I could have anything in the world that I wanted. I told her that she was the most beautiful woman I had ever seen, and that my wish was that I could have sex with her. She said 'I'm sorry mortal, but that is one wish I can't grant you.'"

Confused, the Doctor asked "Well, what did you wish for?"

The man replied "I thought about it, then I said 'Well, if we can't have sex, how about a little head?"