Should animals be used to produce organs that could be implanted in humans?

I think that most people would consider that question to be ethically along the same lines as "Should animals be used in medical research?".

If anything, it seems ethically more "reasonable" to use their organs in transplants than to eat the animal, since eating the animal only provides fuel for a day or so, whereas an organ could give a human around 15 years of extra life (assuming the animal organs had a similar functioning life as a allograft transplant, which may prove to be a bad assumption). However some people will object to this view on the ground of "it involves genetic engineering" or "it puts the animal through unnecessary pain". Some people may just generally feel uncomfortable at the concept of having an animal organ keep them alive.

There are of course additional risks associated with xenograft transplants, however I suspect that under lab conditions necessary to perform the "humanizing" of animal organs, these risks have been accounted for. (E.g ensuring that animals are not carrying any diseases which could be spread to humans). Indeed, knowing that the animal was completely healthy is actually a huge advantage compared to trying to establish the complete medical (and sexual) history of a cadaverous human donor. The "humanizing" of the organs is designed to negate the additional rejection risks associated with "normal" xenograft transplants (i.e. non-humanized xenograft transplants).

If humanized-xenograft transplants worked as well as (or better) than allograft transplants, fewer people would die whilst waiting for a donor organ. They would also be able to schedule their surgery for a particular day. However, I have always wondered whether hospital transplant units would be able to cope if everyone waiting for a transplant were to receive one. (Even as it is, bed spaces, ITU spaces, surgeons, nurses and blood products seem to be a little stretched.) But I like to think that's just my cynicism, and I hope to be proven wrong.