Stan and the nephew.

Stan was seconds away from receiving a vasectomy when his brother and sister-in-law barged in the room holding their newborn baby.

"Stop! You can't do this!" exclaimed the brother.

"And why not?" asked Stan. "Don't you want to have a beautiful baby someday like my wife and I have here?"

Stan said nothing.

The brother grew impatient, "C'mon Stan, I want a nephew. Stan, make me an uncle."

Stan couldn't take it anymore. He gave his sister-in-law an apologetic look and asked his brother, "You're SURE you want a nephew?"

"Yes," the brother replied. "It would be an honor!"

"Well congratulations, you're holding him!"