A death row inmate's request that his execution next week be delayed so he can be an organ donor for his ailing sister isn't the first time a condemned man has tried to donate an organ. But the issue of a condemned inmate donating an organ does raise ethical concerns.

In fact, other death row inmates have been organ donors. And in one case, an inmate was granted a last-minute stay of execution in the hope of saving his dying brother with a transplant.

In this case, Gregory Scott Johnson (search), scheduled to die by chemical injection early Wednesday for the murder of an elderly woman two decades ago, has asked the state parole board to delay his execution. He says he wants to donate a portion of his liver to save his sister, who needs a transplant.

The board is set to consider his request for clemency on Friday, and board members won't comment before the hearing. The panel's recommendation will go to Gov. Mitch Daniels (search), who also hasn't revealed his position on the matter.

No tests have been done to see if Johnson would even be a compatible donor for his sister, Debra Otis.

But the case reopens an old debate about the ethics of accepting organs from condemned inmates. The issue is whether someone in prison has the ability to give informed consent, said Dr. Mark Fox, chairman for the ethics committee for the United Network for Organ Sharing (search), a private group that runs the nation's transplant system.

"Their lives are constrained in ways that yours and mine are not," he said. "Free, informed consent involves the freedom to either to accept or to reject treatments that are being proposed."

Fox said the fact that the donation could prolong his own life could compromise an inmate's decision-making ability.

There also is a concern that Johnson's sister could feel pressured to accept the partial liver from her brother, rather than a full liver from someone who has died, because it might be the only way to extend her brother's life.

"Neither of them may feel they have the complete freedom to make the decision that is appropriate for them," Fox said.

Debra Otis, 48, suffering from non-alcoholic cirrhosis, told NBC's Today show this week that she wants the transplant from her brother. She didn't return calls from The Associated Press.

Other medical ethicists see no problem in Johnson donating part of his liver to his sister.

"A life could be saved and he might be the only person who can do it," said Dr. Arthur Caplan, chairman of the department of medical ethics at the University of Pennsylvania (search). He said the transplant should be allowed if Johnson's liver is compatible and healthy.

Over the years, several inmates have donated kidneys to family members, even in cases where execution dates had been set.

In Delaware, condemned killer Steven Shelton donated his kidney to his mother, Vesta Shelton, in April 1995. He remains alive on death row today.

In Alabama in 1996, the execution of David Larry Nelson was halted by the Alabama Supreme Court less than 24 hours before it was scheduled to see if Nelson could donate a kidney to his sick brother. The brother was too ill to have surgery, though, and later died. Nelson remains on death row.

Others have tried unsuccessfully to donate organs. In 1996 in Georgia, triple-murderer Larry Lonchar wanted to donate his kidney to the detective who helped send him to death row, but then-Gov. Zell Miller (search) refused to allow Lonchar to be tested for compatibility.

In Texas in 1998, Jonathan Nobles' request for a stay of execution to donate his kidney was rejected. Texas prison officials said they opposed the donation because of security concerns, the chance an inmate could transmit a disease and the dilemma of keeping a death row inmate alive if something goes wrong during the surgery.

The whole argument involving Johnson might not matter, however. Dr. Joseph Tector, director of transplants at the Indiana University School of Medicine (search) and Clarian Health Partners in Indianapolis, said Johnson's sister likely would be better off getting a full liver.

Tector, who is familiar with the case, said he is confident he could find a liver for Debra Otis because there is only one other person in the region, which includes Michigan and Ohio, with her blood type awaiting a transplant.

Nationwide, there were 17,336 people on the waiting list for livers, according to UNOS. The median time on the waiting list is nearly five years, said the network's spokeswoman, Annie Moore.

Tector said the median wait in Indiana is about 20 days because the transplant team is more aggressive and accepts livers that other transplant centers might reject.