The better transplant medicine gets at saving lives, the more people it turns into candidates for a new organ. A breakthrough that solves one problem creates an ever-growing demand for cells, tissues and organs that donation cannot meet.
When the buyers are people who will die without a new organ, and supply falls short, many will not wait their turn. Instead they leave the official queue and buy across borders, which feeds a commercial trade that makes up roughly one in ten transplants worldwide.
The global organ market runs in one direction: people in rich countries buy, and people in poor countries sell. Brokers move sellers and buyers together to a third country with lax enforcement, where the surgery takes place. Sellers are often persuaded or tricked, and then get little care afterwards.