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Moral Permissibility as a Guide for Decision Making About Conjoined Twins

Waisel, David B. MD

doi: 10.1213/01.ANE.0000153503.38099.63
Pediatric Anesthesia: Editorial

Department of Anesthesiology, Perioperative and Pain Medicine, Children’s Hospital Boston, Harvard Medical School, Boston, Massachusetts

Supported, in part, by salary from the Department of Anesthesiology, Perioperative and Pain Medicine, Children’s Hospital Boston.

Accepted for publication November 29, 2004.

Address correspondence and reprint requests David B. Waisel, MD, Department of Anesthesiology, Perioperative and Pain Medicine, Children’s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115. Address e-mail to

Decisions about whether to proceed with a therapy often center on whether the benefits of therapy exceed the burdens of therapy. The question in the case presented by Tirotta et al. (1) is whether to proceed with palliative open heart surgery in Twin A of surgically inseparable conjoined twins (Twin B had normal cardiac anatomy). Despite recommendations to the contrary, the parents chose surgery. Because what happens to Twin A happens to Twin B, this scenario skirts the dilemma of how to proceed when the interests of conjoined twins collide. Nonetheless, it is likely that the specter of conjoined twins affected decision making. One possible reason for recommending against surgery is the presumed medical (decreased likelihood of a successful outcome) and social (decreased value of successful clinical outcome) consequences of being conjoined twins.

Rather than speculate on what may have happened in this case, it makes more sense to consider these and other issues in light of a more complete case. Jodie and Mary were ischiopagus tetrapus twins attached at the lower pelvis (2). Because Mary’s heart and lungs were underdeveloped, she was dependent on Jodie’s aortic arterial circulation for life. It was thought that if left together, Jodie and Mary would probably live only a few months and no more than a few years. If separated, it was likely that Jodie would have a relatively normal life; it was certain that Mary would die. Citing deeply held religious beliefs forbidding intentionally causing death, the parents chose not to separate the twins. The physicians thought that it would be in Jodie’s best interests to separate them, however, and brought the matter for legal review. The British Judges ruled that the twins should be separated.

People react in one of two ways upon hearing this story. Some recoil in horror at the idea that one child could be killed for another, even under these circumstances. Others take a utilitarian approach, insisting that it is far better to save one child. These two positions highlight the most pertinent ethical questions. May we separate Jodie and Mary if it will result in the death of Mary, and must we separate Jodie and Mary if it is the only way Jodie may survive?

Conjoined twins are commonly conceptualized as Entangled Singletons, two individual people who are tragically ensnared (2,3). This conceptualization implies that their situation is unnatural and undesirable and demands rectification through separation. It also implies that Jodie and Mary are individuals without interpersonal obligations except those willingly assumed by sisters. This is the underlying approach of most medical and legal analyses. A minority view, worth noting if only to emphasize that the entangled singleton view is not unimpeachable, is that conjoined twins are not simply “two of us, entangled” but are something essentially different, perhaps “two psychologically separate individuals who happen to share a body, the sharing of the body being integral to the individuality of each twin.” (3) Conjoined twins, then, are sufficiently different such that singletons cannot adequately imagine the advantages and disadvantages of being conjoined twins. Applying a singleton version of risks and benefits for conjoined twins is thus faulty, meaning, ultimately, that we cannot assume that the primary goal should be separation. This analysis will proceed using the entangled singletons conceptualization.

Questions on whether it is morally permissible to separate Jodie and Mary center on the death of the weaker twin, Mary (4). One argument in favor of permitting separation is familial altruism, in that we can imagine that Mary may willingly forgo what may remain of her short life to secure the possibility of a longer life for her sister, Jodie. Such behavior is often considered morally permissible within the unique family relationship.

Similarly, we could imagine Jodie insisting on defending herself from Mary. For Jodie, separation is necessary for life. This argument has ethical resonance. Consider two tethered mountaineers, one of whom slips into a ravine. If the stable mountaineer is unable to rescue his dangling colleague and is being pulled over the edge, it is morally permissible to cut the tether, plunging the dangling mountaineer to his death, if the alternative is that they both die. We can imagine Mary as the dangling mountaineer, endangering both Jodie and herself. Jodie may reasonably declare that it is necessity to cut the lifeline. The conjoined twins situation meets the “legitimate necessity” argument inasmuch as 1) the act is needed to avoid inevitable and irreparable harm, 2) no more is done than is necessary to resolve the situation, and 3) the harm avoided equals or exceeds the harm inflicted.

The arguments of altruistic donation and legitimate necessity may not directly address the concern that religious and ethical orthodoxy prohibits intentionally causing death. But some would argue that the death of Mary would not be intentional. The Doctrine of Double Effect suggests that if an action (separation) has an intended good effect (life for Jodie) and a foreseeable but unintended bad effect (death for Mary), the act may be morally permissible if the overall good outweighs the bad. On the other hand, some view the use of the Doctrine of Double Effect to support arguments as ethical gerrymandering. Another argument to support separation is the common religious belief that it is morally permissible to discontinue extraordinary life-support treatment, such as Jodie’s cardiopulmonary system may be for Mary, particularly when the burden far outweighs any potential benefit (5).

These arguments indicate that it is morally permissible to separate Jodie and Mary. “Morally permissible” indicates that an action may be done, but it just as legitimately may not be done. For example, it is morally permissible for the mountaineer to cut or not to cut the tether. The next determination that needs to be made is whether separation is mandatory. If it is mandatory, then physicians caring for Jodie and Mary would be obligated to seek judicial intervention to overrule the parents’ preferences not to separate.

Parents and physicians use the concept of best interests to guide decision making about health care for children. Parents capable of participating in decision making processes are the preferred decision makers for their children, owing to society’s respect for the concept of the family, the assumption that parents care greatly for their children, and the assumption that as children mature, it is likely they will adopt some of their parents’ values, making those values a valid first approximation of the children’s future values.

Yet, society does not permit parents to choose options that have risks incommensurate with benefits. Every child should have an opportunity to develop free from preventable illness or injury (6). Thus, parents may be overruled in the United States if the court is convinced that the parents’ decision constitutes child neglect or abuse. Because overruling parents goes against the grain of society and harms relationships between caregivers and families, overruling parents requires a certainty that doing so will significantly benefit the child. For example, we do not permit parents to refuse potentially life-sustaining blood transfusion for children because transfusion therapy routinely mitigates significant harm with little risk. To override parents, clinicians must show that the option is clearly, convincingly, and overwhelmingly in the best interests of the child.

Of course, this situation is different than the standard best interests calculus in that we are not dealing with one child but with two children. The entangled singleton conceptualization pits Jodie’s best interests against Mary’s best interests. It may certainly be in Jodie’s best interests to undergo separation. But the harm in this case is the premature death of Mary, sister of Jodie and daughter of their parents. Given that overruling the parents involves the death of a bystander, for whom there would be no benefit to the procedure, the bar for overruling parents must be raised.

In my opinion, the question of separation should reside with the parents. Limited knowledge about conjoined twins makes it difficult to make statements with certainty, much less to the level of certainty necessary to override the parents’ wishes. For example, there was disagreement as to how long Mary and Jodie would live as conjoined twins, and although the presumption was that Jodie would do well after separation (albeit with many future operations) such complex matters cannot be ascertained with great certainty. And although the argument that separation is Jodie’s sole chance is emotionally powerful, that argument does not permit overruling parents. Indeed, parents are permitted to forgo chances for their children in the absence of convincing risks and benefits.

Returning to Twins A and B, is it morally permissible to perform palliative open heart surgery in inseparable conjoined twins and should the parents be able to make that decision? Whether the benefit of the procedure is worth the burden is a personal decision. As has been discussed, assumptions about the medical and social future of conjoined twins are hampered by lack of knowledge and experience. Given that the range and likelihoods of outcomes are unclear, it seems morally permissible to proceed with palliation and, consistent with the best interests standard, that the parents should choose whether to have the procedure performed on the basis of their values.

Most of us will not care for conjoined twins. Conjoined twins remind us that as medical technology grows, so does the complexity of data and of moral reasoning. We should be careful not to overstate or understate the certainty of benefits of a procedure. Nor should we let technological abilities sweep us into inadequately considered actions that reject basic tenets of society.

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1. Tirotta CH, Lagueruela R, Munro HM et al. Anesthetic management of conjoined twins presenting for palliative open-heart surgery. Anesth Analg 2005;101:44–7.
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6. Committee on Bioethics, American Academy of Pediatrics: Informed consent, parental permission, and assent in pediatric practice. Pediatrics 1995;95:314–7.
© 2005 International Anesthesia Research Society