One Kidney for Sale - Slightly Used

Last week, a man received a kidney transplant thanks to a stranger he met on the Internet. For a fee, those in need can list themselves on the web site and solicit donors. Both men say that there was no payment from recipient to donor for the kidney - the donor has even volunteered to take a polygraph - but medical ethicists are concerned, nonetheless. To be honest, I'm not sure selling your body parts is such a horrible idea. People often get transplants from outside the waiting list - from friends, spouses, siblings, etc. Without an open market for donors, those with smaller families or groups of friends (or groups that don't match up) are essentially condemned to long-term health problems by accident of birth. Isn't it more just to allow them to buy the needed part from a stranger? Assuming everyone involved is a consenting adult, of course. We don't want it to turn into Dirty Pretty Things, of course.