Today is May 21, 2018 / /
The Lindenbaum Center for Halakhic Studies at Yeshivat Chovevei Torah
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Until the last generation, marriage and reproduction always went together. The only legitimate way of producing children was in the framework of marriage since non-marital sexual relationships are halakhically forbidden or, minimally, strongly discouraged. In our generation, technologies have evolved that enable reproduction outside the context of marriage that do not cross these lines. Consequently, the question arises – is a single man, who does not believe that he will find a marriage partner or there are impairments to his ability to marry, obligated to fulfill the mitzvah of procreation using existing technologies? Does he fulfill his obligation of pru u’rvu when procreation occurs outside of marriage through artificial means?
Practically, there are a number of ways this may be done. Some involve an active paternal role and some procreation without any acknowledgement of paternity:
The three arrangements reflect three models of fatherhood (respectively):
The creation story in Bereshit depicts mating as part of the natural order. All living creatures are created “male and female.” Regarding Adam, an entire parshah is devoted to describing life in the absence of this relationship leading to the statement, “It is not good for man to be alone; I will make a fitting helper for him” (Bereshit 2:18). From the text, it is clear that the natural connection between man and woman goes far beyond the biological need to continue the species. As the words of the Torah indicate, “Therefore a man shall leave his father and his mother, and cling to his wife and they shall become one flesh.” (ibid.24). Appropriately then, as part of a discussion of the mitzvah of procreation, the gemara in Yevamot praises the value of marriage.
Said R. Tanhum said R. Hanilai:
“A man who does not have a wife lives without joy, without blessing, without goodness…” (Yevamot 62b)
This statement in Yevamot as well as many others reflect Hazal’s view of the intimate relationship between man and woman as a source of emotional sustenance that brings joy and nourishes personal growth and development. Marriage and family are part of the complex of legal and religious elements that sanctify the natural bond. This intimate relationship is one of the foundations of the Jewish home and, consequently, the Jewish nation. It is clear then that we have an obligation to encourage marriage and to establish it as the ideal. It is also true that most people want to find a marital partner and to live a fuller life in this way. However, not everyone is successful in accomplishing this. When this is the case, we must ask whether the mitzvah of pru u’rvu still exists. Does the obligation remain? Should we support individuals for whom this is their only consolation, without which they are condemned to loneliness and childlessness, leaving behind no offspring?
The question may be divided into several sub-questions:
Is marriage a pre-condition for establishing a family? Is the goal establishing a marital relationship with procreation as a consequence, or is the aim to have children and marriage is the means to achieving that end? This question is the subject of debate. Indeed, according to Rema, marriage has inherent value as indicated by R. Tanhum in the passage we cited. According to Rema, marriage is a mitzvah independent of considerations of pru u’rvu. On the other hand, Shulhan Arukh maintains that marriage is the means by which the mitzvah of pru u’rvu is achieved and does not have independent standing. It is obvious that one of the mitzvot of the Torah is pru u’rvu and that it is obligatory once one is able to reproduce. Rosh writes explicitly: “If a man took a concubine and fulfilled the mitzvah of pru u’rvu, he is not obligated to marry.” He notes regarding birkat eirusin: “It seems to me that this blessing is not a birkat ha’mitzvah as pru u’rvu (and not kiddushin) is the actual mitzvah.” For Rosh, the focus is not on marriage but on having children; marriage is only a means. This description of marriage as a means for procreation is demonstrated in the Talmud as the statements praising marriage appear in the discussion of pru u’rvu. As stated in Shulhan Arukh:
Every man is obligated to marry a woman in order to be fruitful and multiply.
While this dispute is about the purpose of marriage and not whether procreation is or is not an independent mitzvah, nonetheless, we may conclude from Shulhan Arukh that the primary goal of marriage is procreation. In the view of R. Soloveitchik, there is an inextricable link between the creation of man and woman and the mitzvah of procreation. According to R. Soloveitchik, this view is anchored in the Torah and, especially, the story of the creation of Adam as it is stated: “… Male and female He created them. And God blessed them and He said to them, ‘Be fruitful and multiply…'” (Bereshit 1:27-8). These verses express the notion that the purpose of the physical union of man and woman is reproduction. Consequently, if bearing children is so central, does it indicate that procreation is an important goal on its own, independent of the marital union?
Rambam sets the age at which a man is obligated in pru u’rvu at 17; from that point until the age of 20, a man must try to marry a woman in order to fulfill this mitzvah. It appears then that Rambam links the obligation of pru u’rvu to the possibility of marriage, and that an unmarried man cannot fulfill the obligation of pru u’rvu. Shulhan Arukh sets the age of obligation at 18. In general, the age of marriage is determined by the age at which an individual is sufficiently mature to become a father and a family man. However, Shulhan Arukh also rules, based on the sugya in Yevamot, that a man fulfills the mitzvah of pru u’rvu as early as the age of 13, if he is married. This means that the obligation of pru u’rvu begins with the acceptance of the yoke of mitzvot (at age 13); marriage is but the necessary means of fulfilling this mitzvah.
The Torah states:
“Male and female He created them. And God blessed them and said to them, ‘Be fruitful and multiply and fill the earth…'” (Bereshit 1:27-8).
God turns to the couple, to the two of them together; it seems then that the mitzvah of pru u’rvu is given to them as a couple? When Hazal exempted women from this obligation and ruled that only men were commanded in pru u’rvu, they established the mitzvah as incumbent upon a man while he is still single. He is obligated to marry a woman in order to fulfill his obligation of pru u’rvu.
Indeed, there are many occasions when Hazal refer to procreation as an independent value, not simply a realization of a loving relationship. For example:
“The son of David (i.e., the Messiah) will not come until all the souls in bodies are used” (Yevamot 62a); and: “Anyone who does not engage in procreation, it is as if he sheds blood.” (ibid.63b).
It follows, that procreation itself has value and that the mitzvah applies even when a man is single. Although it is clear that the preferred and recommended way to actualize this mitzvah is through marriage, nonetheless, the mitzvah is incumbent on single men and requires them to marry.
The question of whether one fulfills his obligation of pru u’rvu with a child conceived by artificial insemination is not at all simple. It is not clear whether biological parenthood is a sufficient criterion for pru u’rvu, and it is necessary to determine if parenthood has an additional, formal requirement. Additionally, how do we determine the existence of a biological connection; is the biological relationship simply the transferring genetic material or are there additional criteria? A final question relevant to our examination: is the mitzvah of pru u’rvu fulfilled by transferring genetic material or must procreation take place through a sexual act?
The basic text examining the relationship between a child conceived through the use of artificial insemination and the father is a sugya in Hagigah. The case involves a woman who became pregnant with sperm that remained in a bathtub in which a man had previously washed. Many important questions emerge from the discussion: (1) Is the child a mamzer if the woman is married to a different man, if this man was otherwise sexually prohibited to her or if he was himself a mamzer? (2) Is a child born in this manner exempt others from performing yibum and halitzah? (3) Do the laws of inheritance apply to him? (4) Does he exempt his father from yibum, etc? These questions all relate to our concern – does the father fulfill his obligation of pru u’rvu in this scenario?
Opinions differ on this final question. Helkat Mehokek is in doubt whether the child is considered his. Beit Shmuel reasons that since a married woman is warned not to lie on a strange man’s linens (lest she be impregnated by any semen that may be on the sheets), this indicates that a child conceived through artificial insemination is considered his child. However, Taz indicates that one should not deduce anything from Beit Shmuel’s case. The child may be considered his child li’humra (e.g., the child may not marry his sister), but not necessarily li’kula (e.g., the father doesn’t fulfill pru u’rvu). This appears to be the position of Birkei Yosef: no mitzvah act has been performed; the father’s role is passive and does not determine any outcome. It seems that Tashbetz adopts the position of Beit Shmuel and thinks that the child should be considered the father’s.
Beginning in the previous generation, these halakhic positions have been applied to artificial insemination. R. Uziel, favoring the position of Taz, believed that a child conceived through artificial insemination should not be seen as the donor’s child and the donor does not fulfill pru u’rvu. Not only that, he maintains that artificial insemination violates the prohibition of hotza’at zera li’vatalah. This position is difficult as it is based on an exact parallel between the Talmud’s “bathtub” case and artificial insemination. However, the pregnancy in the “bathtub” case was miraculous, to the extent that R. Hananel thought that there was no tuma’at leidah (ritual impurity due to childbirth) after this birth. Many commentators, in general, deny the possibility of such a pregnancy. Moreover, the questions about the paternity in the “bathtub” case are due not only to its miraculous nature but also for the reason mentioned by R. Yonatan Eibeshitz in Bnei Ahuvah; the pregnancy in the “bathtub” case is one in which the man does not have unassailable knowledge of his role, only indirect evidence. Based on this, how could we arrive at a conclusion regarding the presumed father’s fulfillment of his obligation of pru u’rvu? As R. Eibeshitz stated:
“How could we possibly conclude in the case of a child conceived in the “bathtub” case that the child should be put to death (for striking his father)? Could witnesses ever testify that it was this man’s sperm that impregnated this woman?”
Another reason to deny paternity in the “bathtub” case is the lack of action on the part of the father. This explanation appears in the words of Taz:
“… especially in the case of a mitzvah that must be performed actively (kum vi’aseh), and, in this case, she got pregnant on her own, the father does not fulfill his mitzvah.” This point is also made by Birkei Yosef: “Since he did not have intent to be intimate with her and, in fact, he was not; his act is considered meaningless.”
In cases of artificial insemination, it doesn’t make sense to apply the above positions unchanged. The three arguments cited above which deny paternity in the “bathtub” case are not related to our case for the following reasons:
It should also be noted, that the time gap between the man’s donation of sperm and its insertion into the woman does not change the halakhic reasoning. In general, extending the length of time does not invalidate an act halakhically. Thus, for example, a man may give his wife a get through an agent. Even though the divorce will not be completed until the acceptance of the get which is delayed and done by a third party, nonetheless, this is considered the act of the husband. Minhat Hinukh adopts this approach in his discussion of the mitzvah of pru u’rvu. He argues that the mitzvah is fulfilled not at the moment of conception but long term, through the continued maintenance of the health of the children. Thus, the mitzvah is accomplished, not through the act of sexual intercourse, instead, it depends on the outcome.
Though it logically follows from the halakhic principles I have outlined, that artificial insemination is a legitimate means of realizing the obligation of pru u’rvu, we may not demand that someone fulfill a particular mitzvah through the use of available technologies. Just as it is inappropriate to require a person to connect to an IV in order to fast on Yom Kippur, to do so constitutes a distortion of the Torah’s intention, so too it is inappropriate to inform a single man that this avenue is available to him to fulfill his mitzvah of pru u’rvu and he should make use of it. Instead, we should say that one who uses this method, in all likelihood, has fulfilled the mitzvah of pru u’rvu, though there is no obligation for him to do so.
In addition, while the “bathtub” case involves an unintended pregnancy and is not the result of conscious choice, the use of artificial insemination is intentional. A different aspect of the mitzvah of pru u’rvu comes to light here that is absent from the discussion of the “bathtub” case: is the mitzvah of pru u’rvu fulfilled by the act of impregnation alone (e.g., a man who impregnates a woman and abandons her and the child) or is raising the child an integral part of the mitzvah? I will examine this point in the next section through the lens of child support obligations.
The fundamental obligation of child support (mezonot, lit: food), according to halakhah, lasts until the child reaches the age of six. According to the gemara, one may compel and even humiliate a man who shirks this responsibility. “Yarod yaldah vi’abnei mata shadya.” (The crocodile spawned and threw the burden on the people of the city). The comparison of a man who does not fulfill his financial responsibilities to wild beasts who abandon their offspring, is a sharp illustration of Hazal’s moral critique of such behavior.
Based on this, we rule, “A man must feed his sons and daughters until they are six years old.” Tur adds: “R. Meir of Rotenberg writes that even if the children have assets from their maternal grandfather’s estate, the father is obligated to feed them as the Rabbis decreed that a father must feed his children even if they have the means to support themselves.”
That is, the father’s obligation to feed his children is independent of the economic status of the children or their ability to provide for themselves. Beit Yosef notes, based on Rosh, that a man who had sexual intercourse with a single woman who then bore a child, is obligated to feed the child, and he rules, accordingly, in Shulhan Arukh. Rivash adopts this points of view with the qualification that the obligation of mezonot inheres only when the man admits that the children are his. Otherwise, he may claim that she became pregnant from another man . In contrast, Ran rules that support for small children derives from the father’s financial obligation to the mother. Until the age of six, children are drawn to their mother who feeds them; consequently, they are considered part of her body. In any event, the wife’s food requirements increase and the husband is obligated to provide her children’s food as well. Ran wants to conclude from this that if the mother is no longer alive, the father is not obligated to feed the children. It seems then that when a woman does not have a ketubah from the father, the father is exempt from child support. The view of Ran is not accepted by Rif, Rambam or Shulhan Arukh. Ran himself wrote, “I did not see that the rishonim ztz”l wrote this …” It seems that Ran did not present his view li’halakhah.
According to Shulhan Arukh, a man’s obligation to support his small children is directly linked to paternity and applies to all his children, whether or not he is married to their mother. This is a halakhic obligation and, according to some commentators on Rambam, Rambam believed that it is a Biblical obligation, akin to his obligation to support his wife. According to other opinions, the obligation is a Rabbinic takanah or a stipulation of bei din. In any event, it is not merely tzedakah.
In spite of the halakhic ruling against Ran, some contemporary poskim hold like Ran and even interpret the views of Rambam, Rosh and Rivash in that vein. There are those who maintain that the source of the father’s obligation to feed his young children is part of his ketubah obligations to their mother. According to this view, we need to distinguish between mezonot owed to his children from his marriage to their mother, and those born out of wedlock. In the latter case, his financial obligation is based on one of two halakhic requirement: 1. The obligation is one of tzedakah. This has implications when the children have an independent source of support and are not considered “poor.” In that case, perhaps the father is exempt from paying. 2. The Sages extended the takanah and obligated the father to feed his children even if their mother does not have a ketubah.
Based on this analysis, we see that there are three options regarding a father’s obligation to support his children born to a single woman, most to least extensive (majority to minority views):
In my view, the dispute surrounding this issue is significant. In general, it appears that the a man’s obligation to feed his small children is based on Hazal’s assumption that the proper family structure is marriage with children where the man carries the financial burden and the responsibility for raising the children. Perhaps this is why Ran thinks child support falls within the husband’s marital obligations. However, according to the accepted opinion, li’halakhah, child support is not specifically an element of the Jewish family. Rather, it is a deep moral obligation. The Torah expects a man to take responsibility, to recognize his paternity and to provide for his children even if they are born out of wedlock or from a forbidden sexual relationship. This responsibility, recognized by the halakhah, shapes our understanding of the sperm donor’s role. It informs us that it is best when the father is in the picture, known to the child and serving as a significant support, rather than an anonymous figure whose role is limited to the procreative. In this context, it may be worth mentioning the words of R. Shlomo Kluger (Poland, 1785-1869) regarding fulfilling the mitzvah of pru u’rvu by fathering an adopted child:
I had a doubt whether a man who raised an orphan fulfilled the mitzvah of pru u’rvu, since Hazal stated, “One who raises an orphan is considered as if he begat him.” Based on this, we should say that it is considered as if he fulfilled pru u’rvu…since we say “it is as if he begat him…” According to Taz, it is exactly equivalent and he does fulfill pru u’rvu. However, even according to Drishah, who maintains that he does not fulfill his obligation if he never begat a child, nonetheless, if he had a child who subsequently died and also raised an orphan, he definitely fulfills the mitzvah of pru u’rvu.
According to R. Kluger, raising a child which, according to the words of the Sages is “as if he begat him,” transforms that man into one who has fulfilled the mitzvah of pru u’rvu. While this is still not fully accepted li’halakhah regarding adopted children where the father has played no biological role, R. Kluger’s point is completely applicable to a biological child.
Returning to the three possible types of single fatherhood we presented at the beginning of this discussion (full fatherhood, partial fatherhood and biological contribution without a paternal role), in terms of the mitzvah of pru u’rvu, it appears that we should prefer partial or full fatherhood over biological paternity with no relationship with the child. In addition, it is necessary to distinguish between cases of a terminally ill man who wishes to leave offspring, in reality, fathering an orphan, and other cases.
Indeed, the halakhic dispute between Ran and Rivash may be explained in a different way. In addition to determining whether a man who donates sperm to a single woman should play a paternal role in the life of the child, this dispute also has implications for a larger question – what is the appropriate framework for producing a child. From this perspective, it may be said that the dispute itself reflects a conflict between two values – the value of family and the value of financial responsibility. According to Ran, all paternal obligations are connected to a larger notion of the ideal family structure. Ran’s halakhic stance on the question of child support supports the notion that we should not create new family structures, applying old models of determining financial responsibilities. In his point of view, the disintegration of the traditional nuclear family, the creation of new family structures and alternative frameworks focusing on financial responsibility, is not what the Torah and Hazal recommended. In contrast, the position of Rosh and Rivash is that child support is independent of family structure and, consequently, allows for greater financial responsibility while reducing the necessity for the traditional family. It seems to me, that we should not ignore Ran’s position; though we do not pasken like him, his view should not be totally disregarded given the massive societal changes that have taken place. Ran’s view creates a necessary balance. While we should not foreclose the possibility of single men and women producing children through artificial insemination, Ran’s view indicates that we use this option sparingly, taking into account that “they shall be one flesh” should be a product of “and he shall cling to his wife.”
Marriage in Jewish law is a fundamental value; no one disputes that the proper way for a man to produce a child is within the framework of marriage. This is a basic fundamental truth that requires no proof. I have discussed here tragic cases in which a man has little chance of marrying and wishes to, at least, produce progeny with the attendant joys that come from having children.
A single man is obligated in pru u’rvu. However, he is not obligated to use artificial means in order to perform this mitzvah. Therefore, he is not obligated in this mitzvah until he is married but he can fulfill the mitzvah even before marriage.
One may use artificial insemination. In my opinion, based on the understanding of most poskim, a man fulfills his obligation of pru u’rvu using artificial insemination.
If artificial insemination is being utilized, does halakhah recommend that it be done anonymously or is the preferred mode one where there will be a relationship between father and child? I argue that the creation of an ongoing relationship is preferable. This is learned from the father’s obligation to feed his children until they reach the age of six even when they have independent means of support.
I would add that Shulhan Arukh paskens that a father’s child support obligations include his children born to a single woman. Ran’s opinion, which is not brought down li’halakhah, is that the father’s obligation to feed his children is part of his obligation to support their mother. In my opinion, these views reflect a dispute whether the value of family overrides (Ran) or paternity (Rosh and Rivash, the ruling li’halakhah). Therefore, halakhically, one may not prevent a man who wishes to have a child from a single woman, through artificial insemination, provided that he does not renounce responsibility for his child, since the halakhah values paternity over family. However, in my view, the opinion of Ran must be taken into account in circumstances where marriage may still be possible or in cases where the father will not be able to fully realize his role as father.
 Regarding non-marital sexual relationships, see the summary of the opinions in S. Ariel, Pilagshut einah Haveirut, Akdamot 17 pp. 41-66
 I knew a man who was terminally ill and had not married or had children though he was relatively older. When he became ill, he thought a great deal about having a child so that he could, at least, leave behind offspring. For a while, he sought out a single woman who also wanted a child and was willing to reach an agreement with him. In the end, he died without leaving children. There are quite a few heartrending cases of older men who have struggled to find partners and have given up hope, not to mention gay men, etc.
 In the latter case, the whole question is not relevant, because it is impossible to fulfill the obligation of pru u’rvu with a child who is not considered his halakhically and is, in actuality, not Jewish. Even in the case of a convert who had biological children prior to his conversion, there is a debate among rishonim whether the fulfills his obligation of pru u’rvu with these children. (Tosafot think that he does fulfill pru u’rvu even when the children do not convert along with him. See Tosafot, Yevamot 62a s.v. R. Yohanan) We rule that he does not fulfill his obligation through them. See Rambam, Hilkhot Ishut 15:6, Maggid Mishnah ad loc. and Tur/Shulhan Arukh EH 1:7.
 In such a case, the main question is whether the halakhah recommends this type of arrangement. Some of my discussion here is irrelevant to this case.
 Shulhan Arukh, EH 1:1
 See: Har, Moshe David, Ha’nissuin Mi’behinah Sotzio-economit li’fi Ha’halakhah in: Mishpehot Beit Yisrael, Jerusalem 1976, pp. 37-46, who writes that this position, marriage as a means for procreation, is an innovation of the Torah in contrast to Roman and Christian conceptions of marriage. See also, B. Lau, “Ki hi Hevratekha Vi’eshet Britekha: Shtei Takhliyot Li’mossad Ha’nissuin, Granot 3 (2003), pp. 135-148.
 Rosh, Ketuvot 1:12
 The very appeal to the man and not to the couple in this teaching is sufficient to prove that the mitzvah of pru u’rvu applies to the man before he has a wife. Otherwise, how would it make sense to require him to marry?
 See Rambam, Hilkhot Issurei Biah 15:1; R. Soloveitchik, Adam U’beito, (Jerusalem: 1962) p. 55. It can be argued that the blessing given to man and woman is separate from the instruction of pru u’rvu and that the blessing for man and woman comes by virtue of their partnership.
 Rambam, Hilkhot Ishut 15:2
 According to Rambam, he is commanded to take a woman who is capable of giving birth and to “be fruitful and multiply from her.” Similarly, Rambam brings the mitzvah of onah in the context of pru u’rvu. This indicates that Rambam believed that the mitzvah is incumbent on a married man. See: Rambam, Hilkhot Ishut 15:1,7 and Ha’amek Sheilah, Sheilta 165:1. However, see what R. Bigman and R. Holtzman wrote in their book (unpublished) on this topic, where they suggest that Rambam set the age of marriage according to the prevalent practice, and that there is insufficient proof of an inextricable link between kiddushin and procreation.
 As per Kiddushin 29b
 Shulhan Arukh, EH 1:3
 The age of mitzvot is considered to be the age of sexual maturity, distinct from the age when one is sufficiently mature to marry.
 The gemara discusses whether gentiles who have converted to Judaism or slaves who have been released fulfill their obligation in pru u’rvu with children born to them prior to their conversion or release from servitude. The halakhic questions raised in these situations are, in essence, does one fulfill the obligation when he does the mitzvah during the time that he was exempt? These questions are relevant to our discussion as well. See Yevamot 62b, Bekhorot 47a; see also Yerushalmi Yevamot 2:6.
 Hagigah 14b-15a.
 Indeed, there are those who think that Helkat Mehokek rules that the child is considered his. In the conclusion of this commentary, Helkat Mehokek brings the story of Yirmiyahu and Ben Sira [Ben Sira was believed to be Yirmiyahu’s son though he had no relationship with Ben Sira’s mother] See Helkat Mehokek, EH 6:8; see also Piskei Uziel Bi’sheilot Ha’zman 53.
 Helkat Mehokek, ad loc., Beit Shmuel ad loc.10, Bah YD 195:5, Taz EH 1:8, Birkei Yosef ad loc. 14.
 See Shut Tashbetz 3:263. However, from his closing words it seems that the reason he recognizes the father’s paternity and exempts his wife from yibbum and halitzah is because the father himself acknowledged paternity. Tashbetz does not believe the couple’s statement that the husband was impotent and he thinks that the child was conceived through sexual intercourse.
 Shut Piskei Uziel Bi’sheilot Ha’zman 53.
 See R. Hananel, Hagigah 15a: “This is a miraculous event and she is not temeah due to this childbirth; it does not fit the parameters of “isha ki tazria” (Vayikra 12:2).
 See the summary.
 Bnei Ahuvah thinks that since it is difficult to determine paternity, unlike a standard pregnancy where we attribute the wife’s pregnancy to the husband (“rov bi’ilot ahar ha’baal“), the child would not be put to death for striking his father. See Bnei Ahuvah, Hilkhot Ishut 15:6.
 see fn. 18.
 Birkei Yosef, ad loc.
 Lot’s two daughters become pregnant by their father after getting him drunk and having intercourse with him without his awareness (Bereshit 19:30-8).
 Shut Sheilat Ya’avetz 2:97.
 R. Yehoshua Baumol (Galicia, 19th century) Emek Halakhah 1:68.
 Shut Har Tzvi, EH 4. In my opinion, it is possible to make a distinction and say that even if the child is considered his for purposes of pru u’rvu, this is not the case when it comes to issues of mamzerut since no forbidden sexual relationship transpired. See also Yabia Omer, vol. 8, EH 21.
 However, R. Sternbuch writes that due to the time gap, the sperm became “ownerless” and he is not considered the father. In contrast to the “bathtub” case, where it was the will of God that she be impregnated by this man, in cases of artificial insemination, there are many more factors affecting the question of paternity. See Teshuvot V’hanhagot 3:406.
 See Gittin 2a…, 32a…, etc.
 See Minhat Hinukh, Mitzvah 1, Piryah Vi’rivyah, 1:26, (Makhon Yerushalayim) p. 6, #26. See also Shut Har Tzvi, EH 1, who accepts this explanation and cites it in the name of other poskim as well.
 Nishmat Avraham cites R. Shlomo Zalman Auerbach that there is no obligation for a childless couple to undergo IVF treatments in order to fulfill the commandment of pru u’rvu. It seems to me that this is based on the reason I stated, though R. Auerbach did not specify this explicitly. See Nishmat Avraham, Dinei Piryah Vi’rivyah 1, p. 28. R. Grintz offers additional reasons for R. Shlomo Zalman Auerbach’s statement: 1. This restriction is similar to the notion that one should not exceed more than 5% of one’s income in performing a mitzvah. 2. The Torah’s requirements do not change in light of new technologies.The mitzvah is done through sexual intercourse and dependent then on the mitzvah of onah. Grintz, Tippulei Poriyut – Hovah o Reshut, Adar II, 5774.
 I am discussing here the father’s obligation for a child until the age of six, despite the fact that the obligation extends past the age of six by virtue of takanat Usha as well as later takanot by the Chief Rabbinate. Until the age of six, the obligation is a natural one, and it addresses our question more strongly.
 See Ketubot 49b
 Tur, EH 71
 Tur ad loc. as opposed to the view of Rashba. See Shut Ha’Rashba 2:391.
 I wonder, therefore, whether the father is ever able to exempt himself from child support payments through agreements reached with the mother since such agreements simply change the situation to one where the children have other means of support and, as we just outlined, he should still be obligated. However, we generally say that monetary obligations may be stipulated. Further exploration is needed. In any event, I have completely ignored the possibility of transferring the financial burden to someone else as I am interested in the principle arrangement.
See Avnei Miluim who wrote that the age of six is not fixed and changes according to the development of the particular child: Avnei Miluim EH 71:2. It appears that he believes that even the obligation until the age of six depends on the child’s ability to make a living. In any case, because of takanat Usha the father is obligated to feed a child from ages sex till thirteen, though we don’t enforce this unless the father is affluent. And as we know, the Chief Rabbinate enacted child support; they view this obligation as an obligation of tzedakah , as a result, it differs from the basic threshold we are discussing here.
 Shulhan Arukh, EH 71:4, Beit Yosef ad loc. Beit Yosef relies on Shut Ha’Rosh 17:7 which discusses the case of a woman who married a man when she was pregnant with his child. The husband then disappeared. The ruling was that the husband must pay his child’s wet nurse’s fee as the mother herself was making her living nursing another child.
 Shulhan Arukh, ibid., based on Shut Rivash 41. See on this Shut Peulat Tzaddik 3:20.
 See Ran on Rif, Ketubot 28b s.v. Yafeh Li’halav. See Ran cited in Shitah Mekubetzet, Ketubot 65b s.v. vi’katav ha’Ran; Mishneh Li’melekh, Hilkhot Ishut 12:14; Darkei Moshe, EH 71:1
 Rif, Ketubot 20a in relationship to the daughter of his yevamah, a shniyah (a woman who he is sexually forbidden to rabbinically), his fiancée or the daughter produced by his rape of the mother; Rambam, Hilkhot Ishut 19:14; Shulhan Arukh, EH 71:4.
 Cited in Darkei Moshe Ha’katzar, EH 71. See: Shut Maharam Mi’Lublin 79; Avnei Miluim, EH 71:1. However, it seems that Maharashdam did not reject the opinion of Ran and gave it halakhic weight. See Shut Maharashdam, YD 166.
 However, see Hatam Sofer, EH 1:133 (#4).
 See Shut Yad Efrayim #5. R. Fischel suggests that Tur’s position that child support in a case where their mother does not have a ketubah is because of tzedakah, since Tur wrote (EH 112) regarding support for the daughter of his yevamah, one born of a Rabbinically forbidden sexual union, his fiancée’s daughter or a daughter born of rape: “In all of these cases, we don’t have a clear answer… During his lifetime, the father must feed his children until the age of six based on takanat Usha.” R. Fischel argues that a man’s financial obligations for children under the age of six and born of a kosher marriage is not based on takanat Usha (this is not discussed in Tur, EH 71), as opposed to children whose mother does not have a ketubah where Tur noted explicitly that the obligation is based on takanat Usha. In R. Fischel’s view, Tur is hinting that child support is one of the husband’s obligations in the ketubah; consequently, when there is no ketubah, the obligation is merely one of tzedakah. In my opinion, R. Fischel’s argument is difficult since the laws regarding providing for the child of a single woman are discussed separately in EH 71, not as part of EH 112.
 See: Tashlum Mezonot Ha’banim Mi’kaspei Ma’aser, Or Ha’ma’arav, 4 pp. 23-31
 See R. Klein, Mishneh Halakhot 17:68.
 See Piskei Beit Din Rabbanim 1, pp. 145,154; Piskei Beit Din Rabbani 5, pp. 289, 304-6.
 Hokhmat Shlomo, EH 1.
 See, for example, the position of R. Ariel regarding post-mortem fertilization, Rabbi Y. Ariel et. al., Ha’priyah Li’ahar Ha’mavet – Hebeitim Mishpatiyim Vi’hilkhatiyim, Ha’refuah (2000), p. 331. R. Ariel writes that although there is no prohibition against the use of semen after the death of the donor, whether it was taken while he was alive or after his death, this action is not societally desirable or in the best interests of the child. One should postpone the use of this sperm for a reasonable amount of time, in order to create the space for considered judgment. In the case I am discussing, it is possible that the fertilization and, possibly, even the birth can take place while he is still alive. Nonetheless, there is not much difference between the cases.