Moves to combat "transplant tourism", in which patients from rich countries pay large sums to have organ transplants in poor ones, are gaining pace, experts told an international conference.
In what doctors described as a world first, a Danish woman has given birth to two children after her fertility was restored using ovarian tissue that was removed, frozen, thawed and then reimplanted after cancer treatment.
The World Health Organisation and the European Union have led the way in tackling the problem, the Madrid conference on organ donations and transplants heard.
"Stopping the illegal trafficking of organs and ending transplant tourism is an objective shared by all countries," Spanish Health Minister Trinidad Jimenez said.
"The European Union has a harmonised model in which no one puts a price on an organ, and the WHO is making a great effort to spread this model," she added.
Rafael Matesanz, the head of the Spain's national transplant organisation, said efforts to curb transplant tourism "began in 2005 with the very decisive action of the World Health Organisation and the international Transplantation Society to establish laws in the countries where it does not exist."
Dr Luc Noel, a coordinator of the WTO on the subject, said a "common front" was now emerging in the battle against the practice.
He noted that laws against the trafficking of organs had been adopted in five countries considered among the worst offenders: China, the Philippines, Pakistan, Egypt and Colombia.
In all these countries, many poor people sell their livers or kidneys to patients in rich countries in need of them.
Noel said that although organ transplant tourism continued in China, legislation passed there in 2007 had already led to the arrest of a gang of traffickers.
China's deputy health minister Dr Huang Jiefu attended the Madrid conference to emphasize his country's efforts in this regard.
"Since the beginning of this century, organ transplantation has become a booming health industry" in a country where "over 90 percent of the organs still come from executed prisoners," he said.
"The trading of human organs emerged in China in an under-regulated environment, forming a tremendous profit chain that is against the principles of equality and the goal of building harmonious society in China."
The Spanish newspaper El Pais recently reported the case of a Spaniard, Oscar Garay, who paid 135,000 euros (180,000 dollars) to receive a new liver in a hospital in the Chinese city of Tianjin in 2008.
Huang Jiefu admitted that since the 2007 law, "we still have some hospitals trading with illegal organ agencies and ... selling organs to foreigners for profit"
But he noted that seven hospitals had had their licenses withdrawn for carrying out transplants.
The head of the Transplantation Society, Professor Jeremy Chapman, said "China is working very hard to stop the trade" in organs.
But he said such work must go hand in hand with efforts in the countries of origin of the "tourists"
"To stop the trade you must stop the need. There are some very successfull examples where patients used to leave the country and now they hardly do it at all. I would pick Saudi Arabia as a success story," he said.