“You shall take five shekels each, according to the headcount…” (Bamidbar 3:47)
The Gemara in Menachos (37a-b) records a fascinating discussion between Rebbi and Pleimo regarding a child born with two heads. Pleimo asked Rebbi on which head a person with two heads would place his Tefilah Shel Rosh. Rebbi (who thought that a two-headed human being was an impossibility) thought that Pleimo was mocking him by asking ridiculous questions and rebuked him sternly.
Remarkably, at that very moment, a man appeared and claimed that his wife had just given birth to a son with two heads! He wanted to know how much money he needed to give to the Kohen for Pidyon haBen. An old man (“Hahu Saba”) appeared and cited a Beraisa that rules that a father is obligated to give ten Selaim (shekels) to the Kohen for a child born with two heads, which is twice the usual fee.
The Gemara then questions that ruling. Rami bar Chama says that there is no obligation to perform a Pidyon haBen for a child that was injured (“Nitraf” – became a Treifah) and died before thirty days. Since a two-headed human is surely a Treifah (a person who cannot survive more than another twelve months), the law should be similar and he should be exempt from Pidyon haBen. Why did the Beraisa rule that one is obligated to pay ten Selaim for him?
The Gemara answers that when the Torah outlines the Mitzvah of Pidyon haBen, it says that the payment of five Selaim shall be “la’Gulgoles” – according to the headcount. This implies that a person is obligated according to the “number of heads” he seeks to redeem, hence a two-headed child commands a fee of ten Selaim. The notion that there is no obligation of Pidyon haBen for a Treifah is incorrect. By utilizing the word “la’Gulgoles” the Torah means to teach that the Mitzvah depends purely on the “headcount” and not on the viability of the life of the child.
This is the interpretation of the Gemara according to Rashi. Rabbenu Tam, however, questions Rashi’s reading of the Gemara. If the Gemara (in its question) meant to prove that a child that doesn’t survive beyond thirty days is exempt from Pidyon haBen, it should have cited the Mishna in Bechoros (49a) that states this explicitly instead of inferring this from the statement of Rami bar Chama.
Rabbenu Tam therefore explains the Gemara slightly differently. The Gemara in its question meant to prove directly that a Treifah is exempt from Pidyon haBen. Therefore, it cited Rami bar Chama who rules that there is no obligation to redeem a baby who was injured (read, “became a Treifah”) but was still alive at thirty days of life. Since that child is exempt from Pidyon haBen, the same should apply to a two-headed child who is also a Treifah.
However, according to Rabbenu Tam, the answer of the Gemara is difficult. The Gemara explains that since the Posuk says the word “la’Gulgoles” this teaches us that a child of two heads (who is a Treifah) must have a Pidyon haBen. Why does that not contradict the words of Rami bar Chama that a Treifah is exempt from Pidyon haBen?
The Meiri answers that the word “la’Gulgoles” is used by the Torah only to obligate a two-headed child in Pidyon haBen, not any other kind of Treifah. A child with two heads is an exception to the rule of Rami bar Chama that a Treifah is exempt.
However, as the Chazon Ish notes this answer is still difficult to understand. Why would the Torah distinguish between a regular Treifah, which is exempt from Pidyon haBen, and a two-headed Treifah that isn’t? Moreover, the simple reading of the Gemara is that the word “la’Gulgoles” is cited as a source that one must pay double for a two-headed child, not that we should consider him different than any other Treifah.
The Chazon Ish, therefore, offers a novel interpretation of the Gemara which sheds light on the Halachic status of a child with two heads:
A child with two heads is not a Treifah. Rebbi had originally thought that a child with two heads was a “Neifel” (a baby that cannot survive beyond thirty days), but when he heard that one had in fact been born and survived until thirty days, he realized that he was mistaken. At no point was he considered a Treifah.
Why then did the Gemara ask from the statement of Rami bar Chama that involves a Treifah? The Chazon Ish explains that the Gemara merely meant to derive a general principle from a Treifah, and did not consider a two-headed child as a Treifah. Since one is exempt from redeeming a Treifah, this suggests that Pidyon haBen is only performed for a child that has a “full capacity for life”. Therefore, a two-headed child should not be redeemed for twice the fee of a child with one head, as the Beraisa ruled, because he does not comprise two beings with a full capacity for life. His second head is no better than that of a Treifah who is exempt from Pidyon haBen. However, the Gemara answers that since the Torah uses the word “la’Gulgoles”, the obligation of Pidyon haBen is calculated according to the number of heads. Since the child essentially has “a full capacity for life”, each head is considered to subsist from that, and the father is therefore obligated to redeem both sons for a total of 10 Selaim.
According to the Chazon Ish, the underlying question of the Gemara is “is a child with two heads considered to be one child or two for the purpose of Pidyon haBen?” Were it not for the Posuk of “la’Gulgoles”, the Gemara assumed that we should treat him as one being and redeem him for five Selaim like every other child. But “la’Gulgoles” teaches us that we calculate Pidyon haBen according to the number of heads.
Rav Chaim Soloveitchik zt”l suggested another approach to the Sugya. He also agreed that a two-headed child should not be considered a Treifah but explained the Gemara’s question slightly differently. By invoking the words of Rami bar Chama that exempt a Treifah from Pidyon haBen, the Gemara meant to prove that to be considered a viable “vlad” (child) for Pidyon haBen, it is not enough that the child has a head, he needs to have a functioning body as well. If so, why should the fee for a two-headed child be ten Selaim (implying that there are two “vlados”) when there are not two, functional bodies, just two heads? The Gemara’s answer is that Pidyon haBen does not depend upon the body, but upon the head.
The Halacha (as ruled by the Tur, Y.D. 305) is that a two-headed child commands a fee of ten Selaim for Pidyon haBen.
Returning to the Gemara in Menachos, Pleimo’s question was, “on which head a person with two heads would place his Tefilah Shel Rosh.” Seemingly, he was certain that he need only lay Tefilin on one of his heads but was unsure which one. This again implies that a child with two heads is only considered to be one person, not two, else there should be an obligation to lay Tefilin on each of the heads!
Nevertheless, the Poskim wonder why the law of a two-headed person does not resemble the law of a person with two Orlos (foreskins). A person born with two Orlos must have them both circumcised. Why don’t we say that a person with two heads must similarly lay Tefilin on each of them?
The Beis Yitzchak (Y.D. 2, 99:3) answers that the Mitzvos of Milah and Tefilin are fundamentally different. The Mitzvah of Milah is to remove the Orloh and as long as any Orloh remains, the Mitzvah has not been completed. One must therefore remove all of the Orlos that are present. The Mitzvah of Tefilin is an obligation on a person to lay the Tefilin on his head and arm. Therefore, since we consider a person with two heads to be one person and not two, he need only lay the Tefilin once, on one of his heads, in order to fulfill his obligation.
Tosfos (ibid. ad. loc. s.v. “oh kum”) cites a fascinating Medrash regarding Ashmodai, the king of the demons, who brought a man with two heads in front of Shlomo Hamelech. The man had married and bore children, some of whom had two heads like him, and others with one head like his wife. When he died, each of the two-headed children demanded a double portion in his estate!
Shlomo Hamelech’s decision in the case is not recorded. However, in light of our explanation above, a two headed person, Hilchos Pidyon haBen aside, is categorically one person and certainly only inherits one portion in the estate.
Until this point, we have discussed a single person born with two heads. What about conjoined (“Siamese”) twins?
The Shevus Ya’akov (1:4) contends that conjoined twins are certainly considered to be two separate people as they have two distinct bodies. Only when there was one body (with two heads) did we conclude that it should be considered as one person.
The Ben Ish Chai cites a fascinating case from the Sefer “Ma’aseh Tuvya” (in the name of the Sefer “Even Sinah”) that proves that they are two separate people.
There was a woman in “Eretz Yishmael” who gave birth to conjoined twins who were joined at the hip. When they grew up, one of them wished to marry, but her sister did not agree. They came to a judge to decide their case. The judge asked the sister who did not wish to marry, to stand, but she was unable to do so alone. He then asked her sister to stand and she did so, pulling her up in the process. The judge permitted the second sister to marry as he determined that she was the main partner, with a life force of her own. Her sister was only suckling life from her. Soon after the marriage, the weaker sister died of embarrassment and anger and was soon followed by her sister who died because of the dead body that was attached to her flesh.
The Ben Ish Chai learns from this story that conjoined twins are considered two distinct people, as the stronger sister continued living for a period of time after the death of the weaker one.
 In other words, from the Din of la’Gulgoles we learn that a Treifah is in fact obligated in Pidyon haBen and the exemption in the case of Rami bar Chama is because the child didn’t live beyond thirty days and is considered a Neifel.
 The reason he thought that it should be considered a Neifel is because of the rule “Kol Yesser k’Nattul” – “whenever something is added, it is as though something is taken away” (see Nidah 24a). If so, the existence of a second head, should mean the child will be considered to have “no head” and therefore a Neifel.
 He realized that, in fact, a child like that could survive past the age of thirteen, and therefore Pleimo’s question about the Tefilah Shel Rosh was legitimate.
 A Neifel is barely considered to be a person at all in Halacha. A Treifah is a person who is fatally ill or mortally wounded whose life expectancy is less than twelve months.
 Many Treifos have a perfectly healthy head, but are terminally ill due to an injury or illness in another part of their body. We see from Rami bar Chama that Pidyon haBen only applies to a vlad that is totally healthy and we do not focus solely on its head.
 The Keren Orah suggests that the Pleimo’s question was whether one should place the Shel Rosh on the left-sided head, just like one places the Shel Yad on the left arm (unless one is left-handed).
 The Shevus Ya’akov was ruling on a case of conjoined craniopagus twins (the bodies were joined at the heads such that it appeared as if they had one giant head). Nevertheless, he ruled that they were considered two people
 The Ben Ish Chai (who discusses many Halachos applicable to conjoined twins in Benayahu, Eiruvin 18a) concurred.