Without a living donor, the waiting time for a kidney transplant can extend for many years. Many desperately ill people die waiting.

So it's understandable that some patients turn to transplant tourism -- traveling to another country to buy an organ, usually a kidney.

"I can't believe I would consider going abroad and buying an organ," said Dr. Robert Gaston, a nephrologist at the University of Alabama at Birmingham. "But on the other hand, if this were my child .."

This dilemma has become the subject of a paper recently accepted for publication by the journal Current Opinion in Organ Transplantation. Written by Gaston and another UAB nephrologist, Dr. Hasan Khamash, the paper provides an overview of transplant tourism.

There are few reliable statistics, but rough estimates show that transplant tourism might account for between 5 and 10 percent of organ transplant activity worldwide, Gaston said.

Pakistan and the Philippines appear to be the leading exporters of kidneys. At one time, India and China were the leaders, but recent policy changes have reduced the number of organs coming out of those countries, Gaston said.