GWEN IFILL:Finally tonight: The pleas of two desperate families shift the ethical debate about organ transplant policies for children.

Ray Suarez has the story.

RAY SUAREZ:The cases of 10-year-old Sarah Murnaghan and 11-year-old Javier Acosta have put a national spotlight on the issue. Both have end-stage cystic fibrosis. But they are at the bottom of a waiting list for a adult lungs because they're under 12.

U.S. Sen. Pat Toomey of Pennsylvania, Sarah Murnaghan's home state, says that has to change.

SEN. PAT TOOMEY, R-Penn.: Sarah is being treated by some of the best doctors in the world, and they are convinced that she's an excellent candidate to have a successful transplant surgery. It seems to me a policy that systemically excludes her and other children in her circumstances is a flawed policy.

RAY SUAREZ:Last week, federal district Judge Michael Baylson in Philadelphia ordered a change in transplant policy for both cases, and said the children must be placed higher on the waiting list. That prompted some doctors to say courts have no business deciding on medical matters.

DR. SCOTT HALPERN, University of Pennsylvania Hospital: I don't think we want judges making medical decisions any more than we want doctors deciding Supreme Court cases.

RAY SUAREZ:Now the Organ Procurement and Transplantation Network is setting up an appeal process for children under 12.

For more on the case, yesterday's decision and the issues involved, we turn to Arthur Caplan, director of the Division of Medical Ethics at New York University's Langone Medical Center.

Doctor, the new rules proposed in the vote last night, what would they do? How would they change things?

DR. ARTHUR CAPLAN, New York University’s Langone Medical Center: Well, they don't really change the, if you will, under-12 rule, that is, saying that children can't get organs from adults. What they do do is make a path for an exception, make a path for a compassionate examination of a particular case.

So, if you will, they create an appeals process. It will be in the hands of doctors to make an assessment case by case of whether a younger child could accept or whether organs would fit into a kid under 12 when they come from an adult. We haven't had that appeals process before. So that is a significant change.

RAY SUAREZ:Why were the rules written the way they were in the first place? It wasn't an outright prohibition, but it was a formula that discouraged the use of adult donor lungs in the chests of children.

ARTHUR CAPLAN:The main reason is because adult donor lungs are large and kids under 12 are small, and the lungs don't fit. So you wind up having to use a piece of the lung, if you will, taking out a lobe and putting it in.

Now, unlike other organs, like the liver, the lung doesn't grow back. So a lot of surgeons have felt if you are going to transplant a lobe of lung, that is riskier, more prone to trouble. Others disagree. But the basis of the rule was partly due to the size problem, and then some of the challenges that younger kids pose in terms of immunosuppression, the drugs you have to take after you get a transplant.

Both of those factors were seen as, if you will, diminishing the chance of success by many in the transplant field.

RAY SUAREZ:Now, understandably, in the case of the Murnaghan and Acosta families, you had families going public, heading into the court of public opinion to plead their case. Is that a good place to make medical decisions about transplantation?

ARTHUR CAPLAN:I don't think so.

It is perfectly understandable that a family would say, I'm going to do everything I can for my child, hire a P.R. firm, get my congressman or senator to pay attention. But it's not the best way to allocate the scarce supply of organs that we have.

We have a situation where if you really leave it up to who can mount the biggest publicity campaign, you're not necessarily going to see lungs or any other organs going to those who might benefit the most. So, to me, it's partly -- it's fully understandable that a parent would want to try and save their child.

But you don't want to have a kind of bidding war where people who can spend the most money, who are the most P.R.-savvy, who can wield the most influence with a congressperson are going to win the shot at getting an organ. I think it's better left more or less inside the medical community with the transplant experts to decide who is the best candidate.

RAY SUAREZ:In this area, do medical decisions run on a kind of different track from ethical ones? Are there things that are ethically dodgy that would work medically or medically dodgy that are defensible ethically?

ARTHUR CAPLAN:That's a great question and would take more time than we have got. But the answer is yes.

For example, a lot of programs don't admit people who smoke marijuana. It is seen as substance abuse. On the other hand, we have got two states where it's been legalized, a lot of states where medical marijuana use is accepted. Should marijuana use be an exclusion is partly a medical question, but now it's becoming partly an ethical and legal question in terms of seeing it accepted as part of, you know, ordinary behavior in many parts of the country.

You have fights that break out all time about whether prisoners should have access to organs, whether someone with a severe mental disability should be considered along with others when they need a heart transplant, let's say. So the area is fraught about tough ethical choices.

But I don't mean to say that, you know, it's just up to doctors and just up to transplant surgeons. But, primarily, what you want to know is, what is going to work? What's going to succeed? And then let's argue about other behavioral, psychological, other factors that might impact who goes first.

RAY SUAREZ:Well, give us a thumbnail sketch of how the system routinely works. There are people who need various body parts. There are donors that become available. How does it normally work?

ARTHUR CAPLAN:So it's a two-step process.

One step is, how do you get into a particular transplant center? Each center makes decisions about the kind of patient that they think they could handle. Sometimes, it's money. If you don't have insurance, you may not be up -- accepted into a program that does a lung transplant or a liver transplant. They're costly and people do get turned away because they can't pay.

Citizenship might count. Are you an illegal alien? That might matter to different hospitals. And, as I said, issues around drug abuse, or do you have a criminal record, are you psychologically or psychiatrically very disturbed make it unlikely you could comply. That's the first cut.

Once you get in, all the names of the people who get into a transplant center are on a national list. And distribution from that national list is handled by the United Network for Organ Sharing, a federally chartered group that operates with these rules we keep hearing about.

So think of it as two steps. One, each individual transplant center makes the call. Are we going to take you or we're not? And they may be different place to place. Once on the list, the distribution of organs is handled by a national program with very clear-cut rules about who goes first.

RAY SUAREZ:We're just about at the end of our time. But I'm guessing all these problems are just made more difficult by a shortage of donors.

ARTHUR CAPLAN:They really are. And when you hear about a terrible plight of these families looking for lungs, you have to keep in mind that people are dying every day for want of a heart, lung or liver.

So it's crucial to sign your donor card. It's crucial to talk about that decision with your family so they know that's what you want. Your friends and partners, they should know that's your wishes. And we might give a long hard look in this country against moving to a presumed consent system, meaning, instead of having a policy that says jump into the system, sign a card if you want to do this, let's go with what most people say they want to do, which is to be an organ donor and ask those who don't want to, to opt out.

That would get us more organs, help resolve some of these tensions about who should live and who should die.

RAY SUAREZ:Dr. Caplan, thanks for joining us.

ARTHUR CAPLAN:My pleasure.