Here's a better question:
If it's perfectly ok to donate an organ, whether posthumously or not, then WHY is it illegal to sell it?
If it's mine, and only I can give permission for someone else to have it, then why can't I try to sell it? It's mine.
It brings up the question George Carlin proposed about prostitution: Why is it illegal to sell something thats perfectly legal to give away?
I have mixed feelings about organ donations, but because I'm a cynical fuck sometimes. I am a donor, and I haven't heard a good reason for ANYONE to not be an organ donor, but at the same time if everyone was then not as many people would die, and there are too many people in the world as it is...