Cloning
You’ve seen the episode: group of ne’er-do-wells take a sample of the hero’s DNA, put it in a machine and presto! A fully-grown copy of the hero complete with full memories, exact duplicate of the personality (except modified to be loyal to the ne’er-do-wells) and sometimes even a nifty suit of clothing to go with it. Uh-huh. Now that we really have cloning, let me explain how the Dolly team did it. The cloning team took a tissue sample of the subject; in this case, a piece of mammary tissue from an ewe who had recently given birth. Working under a microscope, the team stuck a long, thin needle into the nucleus of the cell and sucked out the chromosomes. Taking a sheep egg cell, the researchers inserted the donor chromosomes into the egg and zapped the new cell with a milliampere current to cajole the cell to divide. Then they placed it into a surrogate mother for gestation. Repeat about two hundred times until it works!!
Recent efforts have claimed success in as few as a dozen attempts (the Japanese cow cloning team), but either way you cut it, it’s pretty hard to clone someone with our current technology. Also, once you’ve cloned someone, it’s just a new born child. No memory, personality (maybe not [1]) or skills. They grow up at the same rate and are a blank slate. Memory, personality and experience are not genetic traits. They are gained the same way we do: living a full life.
[1] Several people wrote in to point out that being a clone isn’t a complete blank slate. There is some evidence for genes contributing to your personality, but it’s not like all your life experiences are encoded in your DNA.
Some good points here.
I bet they could probably acchieve a “Xerox-style” clone using some kind of molecular assembler, though. I suppose we won’t know for sure until somebody comes up with a real one.