As seen in this Slashdot post in a thread on cloning by "eries":
For those hollerin for cloning tech now, here's a little story from Graham Glass' excellent UNIX for Programmers and Users, Page 410 (SystemsProgramming, Getting a New Process: fork())
"It [fork] reminds me of a great sci-fi story I read once, about a man who comes across a fascinating booth at a circus. The vendor at the booth tells man that the booth is a matter-replicator; anyone who walks through the booth is duplicated. The original person walks out of the booth unharmed, but the duplicate person walks out onto the surface of Mars as a slave of the Martian construction crews. The vendor then tells the man that he'll be given a million dollars if he allows himself to be replicated, and he agrees. He happily walks through the machine, looking forward to collecting the million dollars… and walks out onto the surface of Mars. Meanwhile, back on Earth, his duplicate is walking off with a stash of cash. The question is this: If you came across the booth, what would you do?"
Careful what you wish for.