From Guardian Unlimited (link):

The advert on the China International Transplantation Network Assistance Centre (Citnac) website comes straight to the point: “Organ donors available immediately! Contact us before your condition deteriorates. Remember the best time is in December and January, with the largest number of donors and the shortest delay before receiving a transplant.”

Citnac is a private organisation, based in Shenyang and operating legally under Chinese law. Yet its business, acting as a broker between Chinese donors and foreign patients, is morally questionable. The centre will sell you a kidney, liver, cornea or pancreas, just like any other commodity. But prospective buyers should bear in mind that more than three-quarters of “live” organs are harvested from the bodies of executed prisoners.