Only read this post if you do not get queasy easily.
I was reading a brief press release about research on limb regrowth (not much there really) and a thought hit me: future biotechnology for growing new limbs could have uses for people who haven't even lost a limb. I hear you asking "how?". Here's your last chance to move on to a different post and skip the next paragraph. Really, you might not want to go where I'm going.
The really weird and creepy idea: Cut off a limb in order to grow a new younger replacement limb.
Think about it. Researchers are going to keep pursuing limb regrowth technology. Some other organisms can regrow lost limbs. This ought to be possible for humans 10 or 20 or 30 years from now. Now picture yourself in your 80s with arthritic knees, shriveled muscles, clogged arteries, drooping skin, decayed peripheral nerves, and poor blood circulation to your feet. Well, could you bear to part with your existing legs if you could young and much better legs over the period of a couple of years?
I see the period of regrowth as a big problem. The body normally takes almost 20 years to reach full size. Will future biotechnologies that instruct cells to grow a new limb have to work at a slow pace in order to avoid development gone awry? Or will it be possible to grow new limbs much more rapidly?