Headline-grabbing arrests of kidney brokers and renegade doctors provide glimpses into a global black market in human organs that is thriving from South America to Asia. The World Health Organization estimates that 5-10 percent of the 100,000 organs transplanted each year have been purchased illegally, typically from poor people desperate for cash. In China, thousands of organs reportedly have been forcibly removed from prisoners to feed a lucrative "transplant tourism" business. The full scope of the global organ black market remains unknown because transplant doctors and hospitals either don't know the organs were trafficked or are complicit in the deals. Critics say hospitals should disclose the source of all transplant organs so illegal sales can be tracked. Some doctors say legalizing government payments to organ donors -- as Iran has done -- is the only way to eliminate trafficking, but the mainstream medical community says such payments would only exploit the poor. Artificial organs eventually could help satisfy the growing demand for organs, eliminating the black market.

Sarah Glazer specializes in health, education and social-policy issues. Her articles have appeared in The Washington Post, Glamour, The Public Interest and Gender and Work, a book of essays. Glazer covered energy legislation for the Environmental and Energy Study Conference and reported for United Press International. She holds a BA in American history from the University of Chicago.