Worldwide, about 66,000 kidney transplants are performed annually. By far, that’s too slow a rate to help an estimated 1 million people who have end-stage renal disease.

Is a global market for organ sales the answer? Can a for-profit system exist, save lives, and still not exploit the poor? A series of experts — medical doctors, international health experts, and ethicists — looked at the issue on Feb. 8, in the second of four Harvard conferences this academic year on current controversies in global health.

“It’s an extremely sensitive and troubling topic,” said symposium Chairman Daniel E. Wikler, the Mary B. Saltonstall Professor of Population Ethics, who is on the steering committee of Harvard’s Program in Ethics and Health, a conference co-sponsor. (The other was the Harvard School of Public Health.) “We have here the elements of tragedy.”