When Brenda Winner learned that the child she was carrying would be anencephalic -- born without most of its brain -- she and her husband, Michael, tried to turn tragedy into hope. They asked specialists at the Loma Linda medical center in California to give meaning to their doomed infant's brief existence by using its organs to benefit other infants awaiting transplants.

As it turned out, in December the Winner infant was stillborn, as are most of these babies. Its organs had already deteriorated beyond usefulness. But the much-publicized case, unusual as it was, tests society's definitions of life and death like no other.

Anencephaly is a rare defect of the class that also includes the often crippling spina bifida. Nearly 3,000 anencephalic infants are born in the United States each year, and more than 90 percent of the ones born alive die during the first week, the rest shortly thereafter. This condition's cause is unknown, but it seems to run in families.

The disorder is, as the medical community puts it, "incompatible with life." Physicians will abort anencephalic fetuses up to the moment of birth.

Now that these hopeless infants are viewed as a possible source of organs to save other infants, said ethicist Dr. John C. Fletcher of the University of Virginia, "it has become a matter of balancing two basic ethical principles."

First, he said, "the donor must really be dead. There must be ethical restraints against killing people to benefit others."

"On the other hand," Fletcher said, "you have an ideal donor situation, with the parents as consentful and willing proxy donors." Fletcher, an Episcopal priest, sees "a real need here for compromise."

It was the parents of anencephalic infants who helped Dr. Joyce L. Peabody, chief of neonatology at Loma Linda, arrive at what she considers to be just such a compromise.

"When we started looking at anencephalics as donors about three years ago, I really was not interested in pursuing the matter," she said. "I saw it clearly as a situation of using a baby for the good of another baby, a stranger, and the good of a stranger's parents, with nothing for the donor or the donor's parents." That, she thought, was wrong. "So I pretty much put the matter on the shelf."

Then came Gabriella and Baby Holc, two Canadian infants. Baby Holc was born with a fatal heart defect. Gabriella was anencephalic, kept alive on a respirator. A heart transplant was successfully done at Loma Linda, and today Baby Holc is alive and doing well.

To the surprise of Peabody and others at Loma Linda, the hospital was deluged with calls from the parents of unborn anencephalics, pleading, as eventually did the Winners, that their infants be given an opportunity to benefit another baby, another family.

"We had well over 50 families call us within a couple of months," Peabody said. "What I learned in talking with these parents is that they felt that the normal and healthy parts of their child would have an opportunity to have meaning, to basically live on."

What complicates the case of the anencephalic baby is the way the baby dies. Because of the lack of higher brain function, with only the brain stem guiding basic body functions, the baby "forgets" to breathe. These incidents recur more and more frequently until the baby dies. Each time that happens, oxygen-starved organs are damaged so that when the infant's heart and lungs actually stop for good, the organs are no longer viable.

Let the baby die naturally, and its organs become useless. Keep it alive, and you are maintaining a donor, not a patient.

"When the anticipated benefit was only to a strange child or a stranger's parents, I didn't feel it was a strong enough argument," Peabody said. "But what we're running into now is that the anticipated benefit is not only for the stranger-family, but also for the family of the anencephalic baby. They are the ones who are requesting it. They are the ones who are seeing this as a more meaningful way out of their tragedy."

The practice worked out by Peabody and her colleagues, for use when the parents request it, involves keeping the anencephalic baby on a respirator and then testing periodically to see if the baby can breathe on its own -- one of the key determinants of "brain death" in other children. Moreover, because she is convinced that anencephalics do indeed feel pain, expressed through grimaces and even crying, the moment an infant gives such indication it is removed from the respirator, even if it means sacrificing the organs.

To others, Peabody's is not an acceptable solution.

"You can't get the anencephalic to fit the classic definition of brain death because {the baby} does not have a brain," said Dr. Michael R. Harrison, a surgeon at the University of California at San Francisco. Trying to apply brain-death criteria to them could be the first step in applying those criteria inappropriately to other dying patients.

Instead, he thinks, anencephalics should be in a special exempt category, declared dead prima facie "because there can be no mistake {in diagnosis} and there is 100 percent certainty of death."

That view, in turn, is repugnant to other ethicists, such as Alexander Capron, who contend that medical understanding of anencephalics is so limited that to presume to declare them dead on any existing criteria is without foundation. Anencephalics simply should not be a source of organs.

Mary Vollono of the District, who has had two anencephalic children and is the mother of four other children, is appalled at the idea of "harvesting the organs of these babies while they are still alive. They can still feel," she maintains, and "they are still human babies." It is, Vollono believes, a matter of "giving one person dominion over another's life."

But what, wonders Joyce Peabody, if the tables were turned? What if it became possible to transplant a brain from a mortally injured infant into an anencephalic?

"If the family agreed," Peabody said, "I would just as readily act to transplant a donor infant brain to the anencephalic. We're not dismissing him. We're just not there yet."