While other teenagers were celebrating their high-school graduation, 18-year-old James Chan was in hospital donating most of his liver to his father. "I didn't give it a second thought. It was just something I had to do because my sister was too young (to take the risk)," said the apprentice electrician, who is now 26.
A world-wide shortage of organs has forced many people with end-stage illnesses to rely on living donors - either relatives, or strangers from poorer countries where organs can be obtained cheaply - to donate kidneys, liver sections, lung lobes, skin and bones for grafts.
But the complications and risks for donors - including bleeding, infection and in some cases death - mean that many donors find their own health deteriorating after the operations. "Apart from complications, there is risk of death. In the world's medical literature, we know of 15 (living liver) donors who died after the operation," Lo Chung-man, professor for hepatobiliary and pancreatic surgery at the University of Hong Kong, told Reuters in a recent interview.
For living liver donors, removing one-third of the organ, or the left lobe, carries a 0.1 percent risk of death, while removing the right lobe, or two-thirds of the liver, carries a 0.5 percent risk of death, or 1 chance in 200.
"We are considering someone completely healthy who has no need for the operation and you put him at the risk of death, or 1 chance in 200. For a healthy person, any risk of death is not acceptable," Lo said.
"Our principle is to do no harm, but when we do a living donor operation, we are doing harm to the donor. We are converting him from a healthy person to a sick patient." Chan did not suffer any serious complication, but he is not your average healthy 26-year-old either.
"I can't keep late nights any longer. I used to play rugby, badminton and soccer before the surgery but I tire very easily these days," said Chan, who does not exercise anymore. According to surveys compiled by the Coalition for Organ-Failure Solutions, which combats the trafficking of human organs, 48 to 86 percent of kidney donors in Egypt, Iran, India and the Philippines reported a deterioration in their health, such as being tired more easily and not being able to carry heavy loads as before. Most regretted their decision.
But as long as the vast majority of people in Asia oppose donating their organs upon their death, black markets in poor countries where impoverished people sell their organs, especially kidneys, are likely to flourish.
"It is impossible to say how many are on the waitlist, though from the experience of advanced countries, up to 20 livers are needed for every one million people a year," said Lo.
Yet there are only around 200 livers harvested from dying people in Asia, excluding China, each year, according to experts. In Hong Kong, 150 people are on the waiting list at any time. "We perform about 74 transplants a year, 1/3 using livers from dead donors and 2/3 from living donors," Lo said.
Those in the queue who fail to obtain a transplant die. Unlike kidney patients who can rely on dialysis to stay alive, people suffering acute liver failure cannot wait and most die soon after their livers fail them.
For James, the decision to donate his liver to his father Chan Yeuk-pang was clear, after he was diagnosed with liver cirrhosis and was told he had only months to live in 2000. "There was no other option. My father could have had a transplant in China but it was too unsafe then," he said, referring to as recent as 2000-2001, when the success rates of organ transplants in China were at best 30-40 percent.
"I would do it again if I had to," the son said.