An Irish couple want a black baby more than anything in the world, but all their efforts come to nothing. Finally one day they are walking down the street when they spot a black couple with a beautiful black baby in the pram. So they both walk over, explain their greatest desire, and ask the black couple what their secret is.
"For one thing," said the black father, "You gotta be at least eight inches long!"
"No problem!" replied the Irishman.
"For another," the black guy says, "You have to be at least three and a half inches round!"
"So that's the problem!" replied the Irishman, turning to his wife, "We have been letting too much light in!"