Some readers raised this issue, which I had relegated to a footnote in my article, but which I thought I'd post in response:

Some have argued that allowing organ sales wouldn't substantially improve transplant patients' prospects, because it would decrease the quality of organs available for transplant by attracting providers -- such as intravenous drug users -- who are both especially in need of money and especially likely to have certain diseases. Yet this concern can be easily dealt with without a sales ban. Diseases can generally be screened for, which wasn't true decades ago, when a similar concern drove blood banks to avoid paid providers. And they would in any case have to be screened for, since even charitable donors' organs may be diseased.

Blood banks, including German blood banks that routinely buy blood, operate well with screening. Sperm banks and fertility clinics buy and test sperm and ova; the same approach should work for organs, too. And if compensation generates more organs, doctors can improve average organ quality by being more selective about the organs they use, and by setting aside organs that are not diseased but also not optimal for transplanting.

Note also one item I didn't mention in the footnote: Recall that people who are waiting for kindey transplants have a 6% death rate per year, or over 20% over the duration of the current waiting list. That's a lot of people dying for lack of organs. If compensation yields more organs, and cuts even a year off the waiting list, and at the same time (say) 0.1% of all extra organs are infected in ways that can't be caught by screening (likely a substantial overestimate), that's still a huge saving of life over the current system.

Tomorrow: A brief response to Leon Kass and other people who claim that paying for organs is just plain wrong.