Popular culture has been misrepresenting clones since the term was applied to Homo sapiens. If you want to make the most of the biotech revolution, you're going to have to unlearn the most egregious of culture's misapprehensions.
A Clone Will Know Everything That You Know, and Will Act As You Do
Clones are often depicted in popular culture as experiential as well as genetic copies, sharing some or all of their counterparts' memories, even if the originals are long deceased. In the final (and lamentable) installment of the Alien tetralogy, clones of an alien-Ripley hybrid have access to the memories of the original Ellen Ripley. In Aeon Flux, the members of a society that has for many generations been composed entirely of clones possesses shadowy memories of their past "lives." And in The Fifth Element, Milla Jovovich's character is almost completely vaporized, save for her right hand; lucky for Milla, the genetic engineers of the future need more than a few strands of DNA to completely reconstruct her body and mind. In reality though, this technique would generate at best a genetic duplicate of Milla's body. Her thoughts and memories are contained within the neural connections in her brain, formed during a lifetime of sensory perception: such experiences are not stored in an individual's genetic code. Even if Milla's dismembered hand survived, any memories of her sweet-sixteen birthday party-and everything else for that matter-would be long gone. The biotech revolution promises a number of immediate identity crises, but a genetic clone that also shares your mind is not one of them… yet.
Granted Milla's character was an alien with supposedly "perfect" DNA, so perhaps we should give her the benefit of the doubt. You, however, are human, and unless you're storing backups of your memories in your phalanges, cloning won't bring you back from the Great Thereafter, let alone create a clone that remembers all your email passwords.
Still, what if you could copy your mind as well as your body? Surely this would allow you to come back from the dead, right? In The 6th Day, Arnold Schwarzenegger repeatedly slays a set of unrelenting pursuers, only to find them replaced by seemingly identical enemies after every kill. The villains accomplish this perceived immortality through a pseudoscientific process of copying the memories from their own recently deceased brains and introducing them into the bodies of their brand-new clones. Alas, science has yet to imagine a way to transfer memories from a corpse to a clone. Even if the technology existed, would this new clone really be you, or merely a copy who thinks he's you?
Clones are Decanted at the Same Age as the Original
If you want a clone similar in age to yourself for a long-lost twin, emergency kidney donor, or alibi generator, be prepared for a dip in liquid nitrogen. Your best bet is to cryogenically freeze yourself, hoping that the technology for a successful thaw has been developed by the time your clone catches up with you. Proponents of Einstein may argue that it's easier to flirt with the space-time continuum if you want to temporarily suspend your age, but since none of these proponents has a ride badass enough to travel near the speed of light, the point is moot. Even if you manage to give your clone a chance to catch up with you in the age department, the danger doesn't end there. Your clone will have to be raised by someone whom you trust implicitly, and there's always a chance that she'll simply leave you in the tank and take over your life.
Accelerating a clone's development is technologically far more challenging than postponing your own. In theory, scientists might be able to harness certain diseases that accelerate aging, such as progeria or Werner syndrome, but the progression of aging is dangerously abnormal (victims of these diseases appear much older than their true age, and typically die early in life). The rate at which we develop runs deep in our nature, and even if we're capable of aging the clone in utero so that he is the same age as you (which is a mighty big step), we still have to do something about his learning (which is a mighty bigger step). Unless you can teach the clone in the tank at a comparably expedited rate, you'll end up with an adult duplicate that drools and messes himself, and there's nothing more embarrassing or unsanitary than an attempt to take over the world with an army of clones that missed out on potty training.
Keep in mind that even if we could automatically teach a clone the basics of life-how to feed himself, tie his shoes, and program a TiVo-the basics are not what makes you you. Knowing how to tie your shoes doesn't give you the "muscle memory" of a lifetime avoidance of Velcro trainers. Learning a language from a textbook does not make you a fluent or engaging speaker.
From the book, HOW TO DEFEAT YOUR OWN CLONE: And Other Tips For Surviving the Biotech Revolution by Kyle Kurpinski and Terry D. Johnson. Copyright © 2010 by Kyle Kurpinski and Terry D. Johnson. Reprinted by arrangement with Bantam Books, an imprint of The Random House Publishing Group, a division of Random House, Inc. All rights reserved.