Separating Conjoined Twins: Part I by Rabbi Chaim Jachter


“The ethics and morals involved in this decision are too complex for me. I believe they are too complex for you as well. Therefore I referred it to an old rabbi on the Lower East Side of New York. He is a great scholar, a saintly individual. He knows how to answer such questions. When he tells me, I too will know.”


              These words, referring to Rav Moshe Feinstein, were reportedly uttered in 1977 by none other than Dr. C. Everett Koop, then chief of surgery at Children’s Hospital in Philadelphia, who was later to become the surgeon general of the United States during the Reagan administration.  He made this statement to his staff when deliberating the ethics of a morally wrenching dilemma.  Conjoined twin girls who shared one heart were born to a Kollel family in Lakewood, New Jersey.  The heart had six chambers (a heart normally has four chambers) and without surgical intervention both twins would die within a year since the abnormal heart was unable to sustain both babies.  The only chance of even one twin surviving was to sacrifice one twin in order for the other to survive.,  The parents brought the babies for medical care to one of the world’s leading hospitals, Children’s Hospital in Philadelphia.

              This situation posed a moral and legal dilemma that needed to be resolved in many venues.  Dr. Koop sought and received legal immunity from being prosecuted for the murder of a twin.  Catholic doctors and nurses sought the guidance of their theologians to permit their participation in the surgery.  The parents of the twins would give their consent to the surgery only if Rav Moshe Feinstein permitted sacrificing one twin to save the other.  When Dr. Koop, a deeply religious man who studied Bible every day, was challenged by his staff as to the morality of killing one baby in order to save another, he replied that Rav Feinstein would provide the necessary moral guidance in this most difficult situation.

              In the end, Rav Moshe Feinstein permitted the surgery after considerable deliberation and even fasting over this weighty matter.  He did not, however, issue a written explanation for his ruling.  Moreover, other great poskim such as Rav Yaakov Kaminetsky (as reported by Professor Zev Lev in Tradition Summer 1997 p. 80) disagreed with this ruling.  A number of suggestions were offered to explain Rav Moshe’s decision but none was convincing.  Finally, in the Fall 1996 issue of Tradition (pp. 106-110), Rav J. David Bleich offered a convincing explanation of this ruling based on another ruling of Rav Feinstein that appears in Teshuvot Igrot Moshe Y. D. 2:60.


Sacrificing One Life to Save Another

Normally Halachah forbids sacrificing one life to save another.  This principle is articulated by the Mishnah (Ohalot Ch. 7 Mishnah 6):


 A woman whose life is endangered in hard labor is permitted to have the pregnancy terminated.  However, once the head of the baby has emerged, one cannot touch it as we are forbidden to kill one individual to save another [ein dochin nefesh mipnei nefesh].


This principle is reinforced by the Talmud Yerushalmi (Terumot 8:4) which states:


If a group of individuals on a journey encounter evildoers who say to them ‘Give us one member of your group or we shall kill the rest of you’ let them all be killed and not release even one Jewish soul [afilu kulan neheragin lo yismasru nefesh achat b’Yisrael].


Accordingly, not only can we not kill an individual in order to save the life of another individual, we cannot even kill an individual even to save the lives of numerous people.


A Possible Exception to the Rule

              The Yerushalmi poses a serious question on this principle from the episode related in Shmuel II Ch. 20.  The Navi records the story of a “wise woman of the town of Avel Beit Ma’achah” who hands over the rebel Sheva ben Bichri to King David’s general Yoav ben Tzeruyah.  She did so in order to spare the entire town from being destroyed by for harboring Sheva ben Bichri.  The Navi apparently condones the actions of this woman as it refers to her with the complimentary title “wise woman”.  Accordingly, the Yerushalmi is puzzled why she is complimented when she sacrificed the life of one in order to save the lives of others.

The Yerushalmi cites two explanations for why the case of Sheva ben Bichri differs.  Rabi Yochanan explains that Sheva differs because he was designated for death by Yoav ben Tzeruyah.  Reish Lakish explains that the situation of Sheva is different because according to Halachah, Sheva deserved the death penalty, as one who rebels against the king may be put to death (Rambam Hilchot Melachim 3:8). 

The debate between Rabi Yochanan and Reish Lakish remains unresolved as Rishonim debate whose opinion should be followed.  The Ran (Yoma 82b) and a group of Rishonim rule in accordance with Rabi Yochanan.  This is not surprising since in general we follow Rabi Yochanan over Reish Lakish (Rabi Yochanan is the rebbe and Reish Lakish is the Talmid).  Surprisingly, the Rambam (Hilchot Yesodei HaTorah 5:5) rules in accordance with Reish Lakish.  The Kesef Mishnah explains that since we are dealing with a matter of Nefashot (lives) the Rambam rules strictly.  Interestingly, Rashi (Sanhedrin 72b s.v. Yatza Rosho) cites both Rabi Yochanan and Reish Lakish’s approaches without indicating a preference to either opinion. 

              The Rama (Y. D. 157:1) and the Taz (ad. loc. 7) disagree as to whether we follow Rabi Yochanan or Reish Lakish.  The Rama cites Rabi Yochanan as the primary opinion and Reish Lakish as the secondary opinion.  The Taz rules in accordance with Reish Lakish.  He even cites his father-in-law the Bach who agrees.  This is fairly remarkable since most often the Taz cites his father-in-law and disagrees with him.  Rav Bleich argues that this remains an unresolved matter as to whether we follow Rabi Yochanan and Reish Lakish since a definitive ruling does not emerge from the Shulchan Aruch and its primary commentaries.  The Vilna Gaon (Yoreh Dei’ah 157:16) and Chochmat Adam (88:15), however, rule in accordance with the Rama, presenting Rabi Yochanan as the primary opinion. 

              This debate however appears to be entirely irrelevant to the case of the twins in Children’s Hospital.  Neither child was “designated for death” nor was either baby guilty of a capital crime which would permit sacrificing one child to save the other.

              Some, however, want to argue that since the right side twin had no chance of long term survival it is regarded as “designated for death”.  Thus, it is permitted to sacrifice this twin to save the other.  Rav Bleich rejects this approach arguing that we have no right to follow Rabi Yochanan’s opinion since the Shluchan Aruch and its primary commentaries leave the matter unresolved.  Moreover, he argues that this designated for death refers to a situation as described by the Tanach and Gemara where Yoav Ben Tzeruyah designated Sheva ben Bichri and the case when a bandit singles out one member of the group for death.  Moreover, Rav Bleich cites Rav Chaim Sofer, Teshuvot Mahaneh Hayyim Hoshen Mishpat, no. 50, who argues that "designation" is a factor only when it is within the power of the person specified for death to remove the danger to others by turning himself over to those demanding his life. It is not a factor, asserts Mahaneh Hayyim, when the danger arises because the victim is "pursued by Heaven," i.e., a natural process totally independent of human volition. In the former case, argues Mahaneh Hayyim, the individual is regarded as a rodef because he has the option of delivering himself to those seeking his death; in the case of the child emerging from the birth canal, there is no such option.


Conjoined Twins - One or Two Halachic Identities?

Perhaps a solution to our dilemma lies in concluding that the conjoined twins are viewed as one individual. If we say that the twins share one Halachic identity then we can sacrifice one twin to save the other in the same manner in which a surgeon is permitted to amputate a leg if necessary to save the person.

              The question as to whether conjoined twins are viewed as one or two individuals is already addressed by the Gemara (Menachot 37a).

              Pleemo asked Rebbe [Rabi Yehuda HaNasi], “If a man has two heads, on which one should he place his tefillin (phylacteries)?” Rebbe said to him, “Either go into exile or you will be excommunicated!” (Rashi explains that Rebbe assumed the question was extremely irreverent and mocking.) Just then a man walked in and said to Rebbe Yehuda the Prince, “Our baby that was just born has two heads. How much do I have to give the Kohen (priest) for pidyon haben (redemption of the first born – usually five silver pieces for a baby)?” A certain elderly man came and taught him, “You are obligated to give him ten silver pieces.”

This Gemara establishes only that the obligation of  payment of the sum of five sela’im for redemption of the first born is generated by the emergence of each head that "opens the womb" of the mother. In the birth of ordinary twins, as Rashi explains, it is "impossible" for both heads to present simultaneously. Hence, although there may be some doubt with regard to which twin emerged first, there can be only one first-born. However, in the delivery of conjoined twins, it is entirely possible for both heads to present simultaneously. Accordingly, in instances in which the heads emerge first and both heads are delivered simultaneously, each of the heads "opens the womb. " Since the Torah establishes a requirement for redemption in the sum of "five shekels for the skull" (Chameishet Shekalim LaGulgolet, Bamidbar 3:47) the sum to be presented to the priest is doubled when both heads present simultaneously. Accordingly, the question pertaining to redemption of the first-born is resolved by the Gemara without reference to whether conjoined twins are deemed to be two people or one person.

This question, however, is addressed by Tosafot (ad loc. s.v. Oh Kum) Tosafot, remark, "In our world (baolam ha-zeh) this does not exist," but cite a midrashic narrative relating that Ashmedai, in the presence of Shlomo HaMelech, brought forth "from under the ground" a person having two heads. That man subsequently married and fathered children having two heads like himself as well as children having  one head like his wife. When the time came to divide their inheritance, the two-headed children demanded a double portion of the legacy. The case was brought before Shlomo HaMelech for adjudication.

Shlomo HaMelech's decision, emerges from the same midrashic source quoted by Tosafot, is presented by Shittah Mekubezet, ad locum.  According to this midrashic source, Shlomo heated water, covered one of the heads and then poured the scalding water on the other head. Both heads screamed in pain. Thereupon Shlomo ruled, "It can be deduced that both heads have a single

source and (the twins) should be deemed a single person."

Rav Bleich notes “Unlike Solomon's twins, the conjoined twins described in the medical literature would not both respond to pain stimuli applied to a single head. According to Shittah Mekubezet, such twins must be deemed to be separate persons, not only for purposes of inheritance, but for all other halakhic purposes as well. Moreover, conjoined twins, each endowed with a full complement of organs, are clearly separate individuals, regardless of whether or not they respond individually to pain stimuli.  Accordingly, the twins are clearly viewed as two separate individuals.  Even if one were to argue that “Ein Lemeidin Min HaAgadot“ - Aggada does not serve as a legitimate Halachic source (Yerushalmi Pei’ah 2:4) - since the two girls are clearly two separate individuals, there is no doubt that they have two separate Halachic identities. 

Teshuvot Shevut YaYakov (1:4) notes that according to the Gemara, Eiruvin 18a, and according to one opinion recorded in Ketubot 8a, Adam and Chavah were created simultaneously as fully formed but conjoined individuals and only later were they separated. Shevut Yaakov further asserts that this talmudic opinion concerning simultaneous creation of Adam and Eve serves to establish that twins united in such a manner are separate persons since the Torah refers to Adam and Chavah in their conjoined state in the plural: "Male and female did He create them (Zachar U’Nekeivah bara Otam). . . and He called their name Adam" (Breishit 5:2). Accordingly, Shevut Yaakov rules that twins conjoined in a like manner must be regarded as separate individuals for all purposes of Halacha. Thus, Rav Bleich concludes that at most the right side twin can be classified as a Tereifah (a person expected to die with twelve months; it is Biblically forbidden to kill a Tereifah but does not constitute a capital crime). However, it is not justified to kill this twin based on the argument that it has been designated for death.



In next week’s issue of Kol Torah, we will attempt to connect this discussion to the case ofRodeif, when an individual is attempting to kill someone, to possibly justify sacrificing the right side twin to save the left side twin.

Separating Conjoined Twins: Part II - Rav Moshe’s Position on Rodeif & Relative Degrees of Pursuit by Rabbi Chaim Jachter

Why Did Yonah Flee? - Part II by Rabbi Chaim Jachter and Binyamin Jachter (‘17)