When a young couple from the tiny Maltese island of Gozo visited the doctor for a routine ultrasound test more than one year ago, they had no idea they were about to touch off a global bioethical debate. Yet in the last few months, without so much as revealing their names, they have polarized opinion in scientific, legal, and religious sectors of society.

More improbable candidates to spark a firestorm could scarcely be imagined. The husband, a plumber, labored for a time in Australia to make enough money to marry his sweetheart. She worked in a small shop. The two had just bought a plot of land to build a house for the family they plan to raise. They live in a village that is ninety-five percent Catholic, where Our Lady of Victory Church offers mass seven times a day and where abortion and divorce are illegal.

Their lives were turned upside down when the ultrasound test revealed the couple had conceived conjoined twins—anatomically fused at the abdomen, with heads on opposing ends and legs at right angles to one another. The local physicians recommended the couple travel to England under an agreement that allows a handful of Maltese citizens each year to seek treatment there, so they left for St. Mary's Hospital in Manchester, where one of their doctors had trained.

Having conjoined twins is rare but not shocking; it happens once in every 50,000 births, some forty times a year in the United States alone.

The twins were born in Manchester on August 8, 2000. The prognosis after birth, however, was horrifying. Both babies, the parents were told, could not live; the weaker was dependent on the heart of the stronger for oxygenated blood, and eventually this dependence would kill both of them. The recommendation was to separate the twins, knowing that one would inevitably die but the other would have a chance at recovery.

For the parents, it was a stark "Sophie's Choice"—mark one of your children to die or they both perish.

The names of the parents and the twins have not yet been made public, though England's ITV appears close to inking the inevitable television deal, something the parents welcome as a means of offsetting their expenses. In the meantime, the twins are called Jodie and Mary, referring to the stronger and weaker twin respectively.

Unwilling to sentence Mary to certain death, the parents fell back on their Catholic faith, declaring that the alternative between life and death was for God alone. They declined the surgery. The physicians at St. Mary's Hospital, however, felt a duty to Jodie to intervene. They asked an English court to give them the authority to go ahead with the surgery despite the parents' objection. That court agreed, as did an appeals court on a 3-0 decision, after which the parents decided not to pursue further litigation.

The court's decision did not mandate the surgery. Rather, it held that the procedure would be lawful, should the doctors decide to proceed.

The surgery began Monday, November 6, and stretched over twenty hours into the early morning of November 7, while pro-life protestors staged a quiet vigil outside the hospital. As anticipated, Mary died when the blood vessels she shared with Jodie were severed. Jodie survived and, as of this writing, appears to be in stable condition. She needs at least five more operations that could stretch over as many as five years: her legs are at a right angle to her spine, and these will be straightened in two operations; her lower spine must be reconstructed; her lower internal organs, rectum, and vagina need major reconstruction; and her bladder will have to be rebuilt. Doctors believe, however, that if these surgeries are successful Jodie will have normal intelligence, and should be able to walk and even have children.

The case has raised a staggering range of issues. How much will these interventions cost? Can they be justified when hundreds of thousands of equally innocent babies die in the Third World each year from diseases that linger only because of poverty? Did the surgeons really act in the best interests of Jodie and Mary, or was the operation more a chance for them to win professional acclaim? There is even a suggestion that the wrong doctors are involved, since another English hospital, Great Ormond Street in London, has far more experience in this kind of case. It has carried out twelve separations of conjoined twins of which half survived, while the Manchester hospital had never attempted the procedure. Some observers believe that if Jodie's condition deteriorates, St. Mary's could face legal action for malpractice.

At the core of the debate over Jodie and Mary, however, lie three profoundly difficult questions:

• How can a legal system justify overriding the judgment of parents about the best interests of their children, especially when those parents are obviously neither negligent nor abusive?
• How can one legally defend what, at face value, looks like taking innocent life?
• From an ethical point of view—and most acutely from the Catholic moral framework out of which the parents are operating—can this sort of intervention be justified?

The first question is in some ways the easiest to answer, at least from a strictly legal standpoint. The case arose in the United Kingdom, thus it followed English common law. According to attorney John Kitchingman of the Manchester firm Pannone and Partners, who represented the parents, the courts relied on a common law doctrine called "inherent jurisdiction."

"It goes all the way back to the very foundations of English law, when the king was regarded as the father of the nation and, hence, could usurp the parental role when he felt it was in the nation's interests to do so," Kitchingman told Second Opinion. "That power passed to the Lord Chancellor and eventually to the justice system. It means the court has inherent jurisdiction when it comes to matters of the family."

Built on top of that principle, Kitchingman said, is a piece of legislation called the Children Act, adopted by parliament in 1989 to systematize existing law on the welfare of children. It specifies that when there is a difference of opinion about how to care for a child in a medical, social, or educational setting, the best interests of the child must be the "paramount consideration." It also offers practical requirements, such as a provision that in a conflict involving more than one child, every child must be separately represented by counsel.

Some experts believe English courts have been too quick to invoke the law and overturn the judgment of parents.

"We've gone too far in the last decade…just going along with whatever the experts say," said Richard Nicholson, editor of the Bulletin of Medical Ethics in England. "In the name of giving the courts a tool to deal with negligent parents, the act has justified an unhealthy judicial activism."

Kitchingman told Second Opinion that it is difficult to predict what difference it might have made if this case had arisen in a different jurisdiction, such as the United States, one that lacks a common law tradition or the Children Act.

"Almost inevitably this case would arise under family law, and family law always involves a balancing act among competing interests," Kitchingman said. "Hence it would likely depend on how a particular judge or set of judges decided to strike the balance in a particular set of circumstances. No one has precise rules for this kind of case."

Nicholson noted that American courts have also been willing to set aside the judgment of parents and guardians under certain circumstances. In the case of Prince v. Massachusetts in 1944, the state supreme court found that Sarah Prince could not compel her niece to sell Jehovah's Witness literature in defiance of Massachusetts labor laws. In a famous phrase, the ruling held that parents do not have the right "to make martyrs of their children." Guided in part by that idea, California convicted Christian Scientist Laurie Grouard Walker of manslaughter in 1990 for refusing medical treatment for her daughter, who later died of meningitis. Walker had summoned an accredited Christian Scientist practitioner rather than a doctor. Hence, Nicholson said, there are precedents in the American legal system if a given court wanted to invoke them in a case like Jodie and Mary's.

Some critics of the English decision have charged that had the case been adjudicated in Malta, things would have turned out differently. In fact, however, Maltese courts have overruled parental refusals of treatment for minor children in Christian Science cases, though admittedly it is difficult to predict how a court might apply such a precedent in a case touching more directly on Malta's staunch Roman Catholic heritage.

Even granting that a court may overrule a parent, however, the present case remains troubling because the very same treatment that apparently saved one child involved the death of another. How could the English courts justify an act that may seem tantamount to medical murder?

Legal observers say every step in the chain of reasoning on this point is important because each will help determine the extent to which this case can be used as a precedent. The justices at the appeals level rejected several options. They held, for example, that Mary was a person entitled to full protection of the law, though some analysts encouraged them to regard her as an "invasive growth" attached to Jodie because Mary lacked a developed brain and heart. They likewise rejected the argument that Mary's life was inherently less valuable because it had no prospect of "normalcy" or even significant extension in time.

They rejected the suggestion that doctors should have immunity from charges of assault or murder, rejected an analogy between this procedure and disconnecting life support, and rejected the argument that the doctors were obliged to proceed because Jodie would die without the intervention. They fully acknowledged that the proposed surgery contains both the act and the intention of ending a human life.

In the end, the justices held that when the interests of two patients are opposed and neither can give or withhold consent, doctors must be free to make a judgment about what treatment strikes the best balance.

There was, according to Kitchingman, an obvious attempt by the justices to limit the potential scope of this ruling. Lord Justice Ward specified that the ruling applied only in a situation in which:

• It is not possible to save the life of X without bringing about the death of Y;
• Y will inevitably kill X; and
• X is capable of living a normal life, but Y is incapable of "viable independent existence" under any circumstances.

Nicholson, however, remains unsatisfied. He charged that the court was driven by "a fairly crude utilitarian calculation that some life is better than no life."

"What one then had to do was go through some legal jiggery-pokery to come out with the answer that Jodie had greater claims on the promotion of welfare than Mary," Nicholson said.

Nicholson's criticism begs the larger question raised by the twins. Regardless of what the law may permit, was the surgery morally tolerable?

Catholic leaders who supported the parents believe it was not. In his submission to the appeals court, Archbishop Cormac Murphy-O'Connor of Westminster, the head of the English Catholic church, wrote: "It would set a very dangerous precedent to enshrine in English case law that it was ever lawful to kill, or to commit a deliberate lethal assault on, an innocent person that good may come of it, even to preserve the life of another."

In reaching this conclusion, Murphy-O'Connor was guided in part by analysis of a classic doctrine in the Catholic moral tradition called the "principle of double effect," which in some form goes back to the thirteenth century Dominican theologian Thomas Aquinas. It holds that when an action is likely to have two consequences, one good and the other evil, it is possible to perform the act if the intention is solely to bring about the good effect. In its classic seventeenth century form, the principle stipulates that the means chosen to bring about the good effect must be licit, that the good effect must not be the direct result of the evil effect, and that there must be a "right proportion" between the good and the evil effect. In other words, a small good may not justify an enormous evil.

The Roman Catholic hierarchy in the United Kingdom rejected the application of double effect to the case of Jodie and Mary. "It doesn't work here," Cardinal Thomas Winning of Glasgow, Scotland, told Second Opinion in Rome during the October Jubilee of Bishops. "The good effect cannot follow directly from the evil effect. In this instance the only way you get the good effect, saving Jodie, is precisely through the bad effect, killing Mary," he said.

"How can we justify condemning a human being to death simply because we think someone else's life is more valuable? The best solution is what nature intended—a short life for both of them," Winning said.

In his submission, Murphy-O'Connor suggested that even if Mary's death is merely foreseen rather than directly intended by the surgeons, an "invasion of her bodily integrity" is clearly intended.

"The process of separation cannot be thought of with any plausibility as one of cutting into Jodie's body alone," he wrote. Thus, the archbishop concluded, the case involves a direct evil necessary to bring about the good effect and is illicit from a Catholic moral standpoint.

That conclusion is not universally shared among Catholic moralists.

"The question is, can we accept that the intention is to remove from Jodie a burden on her heart and lungs that, if not removed, will bring about her death?" said Father Brian Johnstone, a Redemptorist priest who teaches at the Alphonsian Academy, Rome's premier institute of moral theology. "If we can, then double effect applies."

"The proposed surgery does not have to be described as killing Mary, and neither is the act in itself killing Mary," Johnstone told Second Opinion. "The test is, is Jodie being saved by the death of Mary? Is Mary's death an end? Strictly speaking it's not. If Mary somehow happened to survive the operation, no one would propose killing her."

Indeed, in announcing the results of the surgery, a spokesperson for St. Mary's Hospital said that Mary had died "despite the best efforts of the surgeons to save her."

Johnstone said that had he been the chaplain advising the parents, he would have told them that it was morally defensible—though not obligatory—to proceed with the surgery. He would also tell them, however, that there are good arguments for not doing so. In the end, he said, the moral calculus is so murky he would leave the final judgment to the parents.

"You reach a point at which logic can't take you any further," Johnstone said, "and I don't see clearly that the state has the right to override the wishes of the parents in this case."

Conservative Catholic moralist Germain Grisez also defended the application of the double effect principle in cases of conjoined twins. He told Second Opinion that he has not followed the case of Jodie and Mary closely enough to make a judgment, but referred to his 1997 publication, Difficult Moral Questions, in which he took up the separation of conjoined twins.

In that essay, Grisez argued that a separation could be justified "in a case in which, without it, both children would probably soon die, while with it one of them probably would survive indefinitely." He reached this conclusion through an analysis of another famous case of conjoined twins, that of Amy and Angela Lakeburg, who were born June 29, 1993, in Chicago. In that case, Amy, the weaker twin, shared a heart and liver with Angela. A separation was performed. Amy died during the procedure, while Angela died just twenty days short of her first birthday.

Although Grisez held this surgery should not have been performed because there was no reasonable expectation of benefit to Angela, he said it could have been justified had there been such an expectation.

"The shared heart and liver were not exclusively the organs of either twin," he wrote. "The chosen means to fashion an adequate heart for the stronger was to cut away the shared heart from the weaker and the chosen means to provide a liver for the stronger was to cut it away from the weaker. That, of course, resulted in her death, but her death was an effect of chosen means that in no way contributed to the ends sought." In a footnote, Grisez notes that Amy's death was hardly necessary for Angela's survival; if a heart and liver could have been transplanted into Amy, for example, it would have had no effect on the hoped-for outcome with Angela. Hence Amy's death was not a "necessary and causative condition of the operation's success."

Grisez ends the essay by identifying two conditions under which a proposed surgical separation that will kill one twin could be justified: (1) without the surgery, the abnormality of the babies' shared organ(s) is likely to result soon in the death of both; and (2) with the surgery, the prospective survivor's prospects are greatly improved. The Manchester physicians treating Jodie and Mary asserted that precisely these conditions applied in their case.

The Catholic debate over the proposed separation of Jodie and Mary seems to pivot on which end of the moral equation one wishes to emphasize: the act or the intent.

"You can describe this action a lot of different ways," said one Catholic moral theologian who asked not to be identified because he wants to avoid "ecclesiastical wars" with the English hierarchy. "The question is, what are you aiming at? What are you intending? No one here is intending the death of the weaker twin."

The moralist used the analogy of a crainiotomy, in which a mother is giving birth and baby is stuck in the birth canal. Unless the baby is removed, both it and the mother will die, because eventually the mother's heart will fail. Is it licit to crush the baby's skull in order to remove it?

"Some would say no, that this is a direct act of killing," the moralist said. "But if the baby was already dead, you'd still have to crush the skull. Your intent is to save the mother. The baby's death does not do you any good, which is what makes this distinct from cases like capital punishment or revenge killing, where you really do need the death to get the intended positive effect. We have to get beyond this nineteenth century physicalist approach, where all that matters is the act itself rather than what you are really aiming at."

The argument seemed persuasive even to many of the Maltese parents' compatriots. A poll in the Maltese Independent just after the appeals court decision showed that 70 percent of readers supported the judgment.

None of that satisfied Cardinal Winning. "We are talking about killing an innocent human being," he said. "Call it what you like, but I worry about a culture that can justify legal murder."

In the end, the only certainty seems that offered by Johnstone: "This case will be studied and debated for a long time. It puts some very fundamental issues on the table."

"I just thank God I'm not in the situation myself," he said.