I read today that heart transplants are becoming quite obsolete. They never really worked properly; 10% of people die very quickly because their bodies reject them, and many more develop cancers and die. The number of donors has also plummeted recently. Many are therefore turning to the possibility of mechanical pumps.

It's hard to argue against this; if you think heart transplants are a good idea, then this is basically just an extension of that concept.

But these people will never get heart disease; they could potentially live much longer. The issue is where this stops... why not make the entire human body pretty much invincible? A focused researched project could achieve it very quickly. The arguments for it are exactly the same as those for the whole of medicine. Are there any arguments against..? And if so, where on Earth is the line drawn?