I believe it is very possible. Not only nanotechonology, but the core instructions at the very DNA itself may be re-engineered (future will be a gold mine for those that reap).
That being said, it brings a very whole new set of philosophical issues to light, such as population dynamics and scarcity of resources. Considering how resources are hoarded by few, I shudder to think of the outcome.
Cosmetic vanity for those that can afford it (what happens to those that can't; survival of the fittest).
Of course, that's what fiction writers are for.=)
There was a good fiction story I read some time back about a senator that was a staunch, vocal religious critic of stem cell research (republican). Yet, when he found out he had Parkinson's or Alzheimer's, he himself quietly went to an offshore center for experimental research to use a stem cell based cure.
Not too far from reality, IMO.