Once upon a time, there was a little baby penguin growing up at the South Pole and one day he went to his mother and said: "Mama, am I a penguin?" His mother replied, "You are my own darling son, I laid the egg you hatched from myself and I love you very much." The little penguin heaved a huge sigh, "Okay..." and waddled off.
A few years went by and the little penguin learned how to swim and how to fish. He tried the whole flying thing, but it didn't really work out for him and again he went to his mother and he said, "Mama, are you really, really sure that I'm a penguin?" His mother said, "I am a penguin. I laid and egg, you came out of it, you are a penguin." The little penguin heaved a huge sigh, "Okay..." and waddled off.
A few more years went by and the little penguin was finally a grown-up penguin. He was all ready to marry another little penguin and raise a penguin family with her. The night before his wedding he went to his mother and said "Mama, level with me: are you absolutely, really, truly, cross-your-heart-and-hope-to-die sure that I am penguin?" His mother replied, "Alright, look - I am a penguin, your father is a penguin, our parents are penguins, their parents were penguins, the very first penguin who ever said 'I'm tired, I'm just going to take a break from flying' was your great-great-great-great-great-great grandfather, all your relatives are penguins, everyone I have ever met is a penguin, what is wrong with you, why the hell do you keep asking me this?!?!?!?"
and the little penguin replied "Because I'm freezing my BALLS off here!!!!"