Once upon a time there was this sperm called Brian. Brian was a very health conscious sperm who spent all his time doing push-ups, sit-ups, somersaults and generally charging around the testicle being fit, while all the other sperms just slobbed about the place doing nothing. One day, one of the other sperms roused himself long enough to become curious, and asked Brian why he exercised all day. Brian said "Look pal, only one sperm gets to make a woman pregnant, and when the right time comes, I'm gonna be the one." A few days later, they all felt themselves getting hotter and hotter and they knew that it was getting to be their time to go. Then they were abruptly released and sure enough, there was Brian swimming far ahead of all the others. All of a sudden Brian stopped, turned round and began to swim back with all his might.

"Go back! Go back!" he screamed, "It's a b**w ***!"