Greg Mankiw has a very interesting post today about kidney donations and quid pro quo.
I'd like to think he's making a common sense point, but I don't know how common his view is. According to one Dutch survey, most people (in the Netherlands presumably) seem not to like the idea of compensating kidney donors. Oddly, they were more comfortable if the donor were compensated with health insurance than if he were compensated with cash.
One objection would be from egalitarians: the rich would keep both of their kidneys, while the poor would be more likely to donate one (and undergo a potential dangerous surgery). But they are freely taking this risk and feel that they are better off taking the risk than not taking it (they get money and they have saved a life). The counter-counteragument is that they may be making the choice under duress, so it's not completely free. But this seems like it's something that could be quite difficult for us to know. And trying to prevent people from making transactions for the wrong reasons is a little bit too much micromanagement in my opinion. By similar logic we could ban unemployed people from going to law school. They didn't really want to take on all that debt. They were just desperate.
It's not intrinsically wrong, as far as I can see, to donate a kidney to make money. So, I'm willing let many thousands of people do it, knowing that maybe a few will do it without having completely pure intentions or without fully thinking the decision through, if we can save many thousands of lives in the process.