Nearly 11,000 organs were purchased on the black market in 2010, and about 10,000 of those organs were kidneys, according to the World Health Organization (WHO).

"The illegal trade worldwide was falling back in about 2006-2007—there was a decrease in 'transplant tourism,'" says WHO physician Luc Noel.

However, evidence gathered by a global network of transplant surgeons and physicians who treat end-stage renal failure suggests that increasing diabetes and high blood pressure rates have contributed to a boom in the kidney black market, which now trades more than one kidney every hour worldwide.

“The stakes are so big, the profit that can be made so huge, that the temptation is out there," Noel says.

According to WHO, many illicit transplant operations take place in China, India, or Pakistan, where organ brokers will pay as little as $5,000 for kidneys and sell them for as much as $200,000.

According to The London Guardian, an illegal organ broker in China recently advertised “Donate a kidney, buy the new iPad!” and offered about $3,900 per kidney.

Altogether, experts estimate that 10% of all organ transplants are conducted on the black market. In 2010, 106,879 legal and illegal donor kidney were transplanted in WHO's 95 member states, but only 10% of the worldwide organ need was met (Campbell/Davison, The Guardian, 5/27; UPI, 5/28; Fox News, 5/28).