NEW YORK — A Turkish peasant claims one of his kidneys was stolen. Philippine prison inmates trade organs for reduced sentences. Brokers in human body parts take their cut of a shadowy market.

The forces of supply and demand in the desperate world of organ transplants have created a commercial trade in human organs that worries health officials and ethicists worldwide.

The need for organs to replace faltering body parts is growing as research advances and surgery is more successful. But the number of donated organs has failed to keep pace. Doctors say too few people die in circumstances that provide transplantable organs. When they do, relatives are often too grieved to donate a loved one's organ or object for religious or cultural reasons.

What to do about the organ trade varies. The United States, Japan and West Germany have banned it. In India, such trade thrives legally. Lawmakers in Britain and the Philippines have just begun grappling with the matter.

"There simply doesn't seem to be any country that has a public policy to generate enough organs to meet the demand," said Arthur Caplan, director of the Center for Biomedical Ethics at the University of Minnesota.

The World Health Organization in May called for a global ban on commercial trafficking in human organs. Dr. Ursula Lehr, the West German health minister, spoke for the ban.

"The idea of business-minded brokers taking advantage of the financial distress of people in the Third World, buying their organs for a pittance and reselling them to wealthy patients in developed countries, is awful for me," she said.

But some ask, what's wrong if people, fully informed of the risks, decide to sell one of their organs, for example, a kidney? The question, however, becomes complicated when the potential donor is desperately poor. People can live with one kidney, and offers for transplantable kidneys have ranged in individual instances from $3,000 to $20,000.

"Is it really for us, who are not faced with those difficulties and that heart-rending decision, to deny people that choice?" Neil Hamilton, a British lawmaker, asked in recent parliamentary debate.

"It really isn't a choice if you're coerced by poverty," said Caplan, the Minnesota ethicist.

Others worry that selling organs would decrease the supply of donated organs and make transplants more expensive in general.