Thousands of Americans who need transplants die every year because they cannot find a suitable donor, advocates say.
They propose a controversial way to encourage more people to come forward: Pay them.
"It is widening the donor pool. A lot of times employers don't pay for the time off that these donors take from work," says Doreen Flynn of Lewiston, Maine.
"So I think in those instances those people can say, 'you know I can do that,' knowing that there will be a support system for them at the end."
Ms Flynn's three daughters have a rare genetic blood disorder called Fanconi Anaemia. Their bone marrow does not make enough blood cells to keep them healthy and their only hope for survival is a transplant.
It is against US law to sell body parts - including bone marrow. But last year, Ms Flynn won a court ruling in favour of compensating donors whose blood stem cells are collected using a process called aphaeresis.
Instead of undergoing surgery to remove the fatty tissue containing the cells, donors are given medication that stimulates stem cell production. The surplus cells are forced out of the bones and extracted from the blood stream.
The procedure is comparable to giving blood, campaigners say, and the judges who ruled in her favour said it rendered the phrase "bone marrow transplant" obsolete.
But the Obama administration has appealed the ruling. It argues the aphaeresis contravenes federal law banning the sale of human organs - including bone marrow.
Jeff Rowes, a lawyer for the Institute for Justice, which represents the Flynn family, says the law is out of date.
"When congress passed the National Organ Transplant Act in 1984, you could only get these blood stem cells out of the bone marrow by sticking a needle in your hip," he says.
"Now, you can get the blood stem cells the same way that we donate other blood components like plasma and platelets. You can compensate donors of plasma and platelets and there's no reason why you shouldn't be able to compensate bone marrow donors when you get the cells in exactly the same way."
The government challenge is a major setback for the Flynn family, who are running out of time to find a match for 13-year-old Jordan.
She's become so sick doctors have only a couple of months left to perform a transplant with the most suitable donor they can find - and even that won't guarantee her survival.
"The whole process of getting a transplant scares me because I know people who passed away afterwards," Jordan says, sitting in her bedroom decorated with posters of Justin Bieber and other teen idols. "But I try to stay positive."
Her seven-year-old twin sister's health is also beginning to deteriorate.
Jorga and Julia were conceived in the hope that their healthy bone marrow could be given to Jordan (children of two parents who carry the Fanconia gene have a 25% chance of being born with the disease). But embryonic screening failed to detect that they too suffered from Fanconi Anaemia.
Despite the desire of the Flynns and other families to boost their chances of finding a match, the National Marrow Donor Program strongly opposes any financial incentives for donors, regardless of the medical procedure.
People who want to sell organs are more likely to withhold medical details and other information that could harm organ recipients, the organisation says.
"Our experience and research show that a donor system that relies on the human desire to help others is far superior to one that focuses on self-gain," the organisation says in a statement.
Some doctors are concerned about the risk, but Dr Imad Tabbara, head of the Bone Marrow Transplant Program at George Washington University Medical Faculty Associates, says unsuitable donors are eliminated through screening.
"It used to be a concern that donors may carry certain infections or certain viruses, but with the technology we have now in terms of screening across the board, I don't think that should be a problem."
He also predicts compensation would increase the pool of minority donors - Asians and African Americans in particular are underrepresented on national registries.
There are 9.5 million registered bone marrow donors in the US and the National Marrow Donor Program has access to millions more around the world.
But it can take several years before prospective donors are matched with a patient, by which time they may be unwilling or unable to continue the process, says Mr Rowes, the Flynns' lawyer.
He thinks compensation will provide an extra incentive to follow through. And he stresses that the payments will not be made in cash, but in the form of $3,000 scholarships, housing allowances or a charitable donation that would be administered as a pilot program by the non-profit group, MoreMarrowDonors.org.
The Obama administration has asked the US Court of Appeals to rehear the case. If, as is expected, the court declines, it could go to the Supreme Court to decide whether science has advanced far enough to eliminate the ethical questions surrounding payments for bone marrow donors.
Mr Rowes says patients should be allowed to decide for themselves the risks of taking organs whose donor has been compensated.
"When somebody needs a bone marrow transplant, it's because they're dying," says Mr Rowes. "Their death is imminent and certain. No donor equals death."
http://www.bbc.co.uk/news/magazine-17346797
