The husband's sperm is not inseminated into the woman's uterus but into a test tube. On the woman's side, there is no insemination either. Instead, an egg is surgically removed from the ovary and placed in a test tube. Outside the woman's body, in the test tube, in a place that has no relation, is where the fertilization process occurs. The fertilized egg divides there several times. Only after several divisions (after several days or a week or more) is fertilization guaranteed, and only then is it implanted in the woman's uterus. It follows that there is no insemination in the usual way, either on the part of the man or the woman. Both are inseminated by a third party into a test tube. The fertilization that leads to pregnancy and birth, which is performed by a third party in a test tube, is also performed in a manner that is not customary, and the third force is the test tube (which is not even a creature)...

And I saw evidence being brought that Dinah was a daughter of Jacob, which is explained in the blessings that she became from Rachel's womb to Leah, and Joseph from Leah to Rachel. If so, even though the conception of Joseph was in Leah's womb, in any case he was called the son of Rachel, since the main part of the pregnancy and birth was with Rachel...And it seems that the evidence should be rejected and one cannot make a proof from a miracle, since the fundamental logic is that the owner of the egg is called the mother, who has a share in the child and in its specifics is like her...

In my humble opinion, it is obvious and without contradiction that certainly, only Joseph's body in Leah's womb became female and Dinah's body in Rachel's womb became male, and so their souls were exchanged from one womb to another, so that when Joseph's body in Leah became female, Dinah's soul from Rachel's womb entered her, and vice versa, and this is clear.

Indeed, according to the opinion that the foetus is the thigh of his mother, and yet he believes that when a pregnant woman converts her son does not need immersion, on the grounds that there is no barrier here, because it grows with it and works for her child, as explained in Yevamot, there, and yet she is considered as his mother, this is evidence that the birth mother, even when the child is not hers, because her conversion came and made the foetus like a newborn, [yet] the birth causes her to be considered the mother and [the child] is subject to the obligation [of not sleeping with] his brother's wife. From this it is proven that it is enough for birth to make the [birth mother] considered his mother and to prohibit his brother's wife from his mother. And from now on, since according to the view that the foetus is the thigh of his mother, it is necessary to say that a separate birth causes him to be considered as a mother, so also according to the view that the foetus is the thigh of his mother believes so, since we do not find that there is a difference in this opinion, why should I say that there is a difference and believe that a birth does not make a mother...

And one should look at the case of a non-Jew who sleeps with a non-Jew and they take out the fetus and put it into the womb of a Jewish woman, in which case the son needs conversion and is like a non-Jew who converts, whose child needs immersion. Indeed according to the view that the foetus is its mother's thigh, it is made a Jew by birth alone without conversion, for even though it was the thigh of its nono-Jewish mother, nevertheless it was made the thigh of its Jewish mother and it is like a pregnant woman who converts where it does not need immersion since it is now like the thigh of a convert, even though it was the thigh of a non-Jewish woman.

...the conclusion is not supported by this source. Firstly, the analogy of a convert mother to a transplant mother is flawed...Secondly, the principle that a convert has the status of a new-born only serves to eliminate previous familial relations, but not to erase historical facts. That the children born to a pregnant proselyte are brothers only indicates that the relationship between them and their mother is established at the time of birth, but not that birth is the cause of the determination. It is possible that ovum donation determines maternity, but the relationship is established only when the child is born...Thirdly, the proof is based on two assumed premises not explicitly stated in the source: first, that the embryos are considered to have converted; second, that hence all pre-conversion relationships are annulled.

Even though one who converted is like a newborn, and so find does not have her parents, nevertheless they did not say that a gentile who converted is considered a newborn with regards to the convert himself not being the same person as before the conversion and as if he is a new man, for if so then a non-Jew who borrowed money and converted would not be obligated to repay because it would not be the same person who borrowed...and in my humble opinion, it seems we only see this regarding relations with others, that after conversion one is no longer related to their relatives and they are fit for testimony and permitted in arayot but we do not say that he himself is no longer the person he was previously, therefore he is obligated in everything which he was obligated in before he converted.

It is not demonstrated by the proof from the pregnant woman who converts. There it is clear that birth can establish motherhood, but that is not to say that parentage is established except in that case, where conversion severs the relationship with the mother, and then birth establishes [motherhood]. But in our case, where the foetus is transferred from a Jew to a Jew, it is possible that the [genetic mother] is preferenced, and particularly when she is prior [in the process to the birth mother].

One might reason that this is because, lacking “the form of a human,” the embryo is not considered a human being. Alternatively, one might conclude that prior to forty days, a woman is not pregnant, and, according to this model, that is because human life has not flowered within her….Implantation in in vitro fertilization is performed far earlier. The zygote is microscopic at that point, and, as Rabbi Bleich has pointed out elsewhere, “an organism that can be seen only by means of a magnifying glass or under a microscope is an organism of which Jewish law takes no notice…]. Essentially, a fluid without any particular components is being injected into the woman…Furthermore, the fact that the zygote has no mother while in vitro would itself be a reason to deny it personal identity. This, in turn, might allow us to view the implantation into a human womb as the equivalent of organ transplant, where the transplanted material loses its original identity and becomes part of the host.

See Niddah 31a...this implies that the parentage [is established] at the time of the seed. The development of the child in the mother's insides is just a place of growth...

And it is examined in the Shas Sanhedrin (Exodus 2:2) that the soul was given to a person from the time of the office, as it is said, and their commandment preserved my spirit.

The question we are considering, who is considered to be the mother, can be divided into different details like the prohibitions of incest, respecting one's mother, inheritance and the like, and there is room to say that each question is independent...

The Gemara does not distinguish between a foetus where the conversion occurred before or after forty days...

The very term "its own womb" indicates that conception creates a relationship between the mother and the embryo; the question of the Talmud is whether the laws of the first-born, which are dependent on "that which opens the womb (peter rehem), could apply to a womb of an animal that was not the mother...At the very least, this source demonstrates that in a case of embryo transfer, where an embryo is removed from a woman who conceived it, she is considered the mother. This could, however, be due to the fact that the removal from the first woman is in fact a birth, although the term, "its own womb" does not support this interpretation.

And do not challenge from what is written in Chullin 70a...even according to the view that exempts, that is not because it is regarded as giving birth to a child, [rather] that this 'birth' which is not from her also exempts...the whole doubt is whether the opening of the womb [needs to be done] by her child or whether it is sufficient even if the womb is opened by a child that is not hers..

I would like to tell the Rabbi that I was once sent to ask Maran HaGris Elyashiv Shlita about a priest whose wife is unable to give birth, and an egg from her was fertilized with her husband's sperm, and implanted in a gentile surrogate. The Rabbi was angry about the act itself, but he ruled that the births (three sons were born) be circumcised according to the law, but he said that their ruling regarding the priesthood is doubtful, and I did not have the privilege of understanding the doubtful side of this.

And the bottom line is that the egg donor is the mother after all, and the surrogate is like an incubator in a hospital.

And come to your own conclusion, if they take the seed of a dog and a female dog, implant it in a Jewish surrogate, and she gives birth to a puppy, will they circumcise it at eight, and say, "And the mother shall be known by her offspring"?

As far as I know, Rabbi Yosef has not expressed his opinion in writing in his books and articles published to date, on the issue of egg donation and ovarian transplantation.

In this regard, in the month of Adar 2, 2008, my friend Rabbi David Toledano, head of the Beit Midrash Or LeZion in Los Angeles, wrote a summary of his conversation on this subject with the Rishon LeZion Rabbi Shlomo Amar: "Maran Rabbi Amar told me that the opinion of Maran Rabbi Ovadia Yosef (shlita) is that in fertilization from an egg of a foreign woman, the embryo is related to the woman from whom the egg was taken, and not to the "mother" who grows the embryo in her womb and gives birth to it."

However, at the time of the incident, I heard from people who came to the house of Rabbi Yosef, who in many cases permitted egg donation only from a Jewish woman who was available, and ruled that the child is related to the woman who gave birth, and not, as Rabbi Amar had stated in his name, that the child is related to the owner of the egg.

In the month of Tammuz 5768 (2008), I entered the residence of the Rishon LeZion, Harav Amar, and asked him what his position was. And Rabbi Amar repeated what he had heard from Harav Yosef that the child refers only to the owner of the egg and not to the woman who gave birth at all...

Upon completing the draft of this article in the winter of 2009, I entered the room of Rabbi Yosef to inquire about his opinion on this subject in detail, and the Rabbi asked me to leave the article for his review. Afterwards, my friend Rabbi Yitzhak Pinz, one of the editors of his books, informed me that the Rabbi had reviewed the article and his position on the issue of egg donation and surrogacy is as Rabbi Amar said on his behalf – that the owner of the egg is the mother.

When he served as Israel’s Sephardi chief rabbi, Amar insisted that pro forma conversions were not necessary for children of Jewish ovum donors, while bona fide conversions were entirely required for children of a Jewish gestational mother.

But if it were not the case that the immersion worked for him, the foetus would remain a non-Jew. And even with birth, even if the mother converted and is a Jew, the child would be a non-Jew...with regards to our question, we find there is a practical difference regarding whose eggs are placed in whom. Where a non-Jew's egg's are placed in a Jew's womb, the offspring is not Jewish. And likewise if a Jew's eggs are placed in a non-Jew's womb, the child is Jewish. And if a Jew's eggs are placed in the womb of another Jew, the birth mother is the mother...and there is no practical difference whether it was removed before forty days from conception or after as demonstrated from the proofs we brought. However, if they removed the fallopian tube - from which the woman's eggs came - from the non-Jew into the Jew's womb, then it is certain that they lose the non-Jewish designation and turn into the Jew's because they are nullified to the crux of the body, which is not the case regarding separated eggs which receive the independent title of being a foetus...

And in my humble opinion one can say that since both women ultimately work to create the offspring and its development, and one cannot exist without the other, there is room to say that both of them are equal to a mother and that the offspring has two mothers. And similarly, we find in Tosfot in Sotah (44:2) that there is a scenario where the offspring has two fathers...And in my opinion, one should be concerned in a stringent way for all the explanations we mentioned, namely, that either the genetic mother is the mother, or the surrogate mother is the mother, or both the genetic mother and the surrogate mother have some degree of motherhood. And it is appropriate to be concerned, since we have no sources from earlier authorities, and God help us, and they will not do so in Israel.

Previous secular and halakhic articles on gestational surrogacy are based on the traditional position that a surrogate mother serves as a “substitute womb” to nurture and gestate a genetically unrelated embryo without significantly contributing to the future physiological or behavioral attributes of the child. This position is no longer tenable. Emerging scientific data on maternal-fetal cellular transfer and epigenetics transform the role of a surrogate as a substitute womb into a cooperative health partnership between the surrogate, the fetus, and the biological parents...In 1893, data were first presented showing the presence of fetal cells in the lungs of 17 women who died from complications of eclampsia. Since then, more than 1,000 scientific journal articles have presented data showing that during pregnancy stem cells from the fetus traverse the placenta and implant into various tissues of the host mother. These implanted fetal stem cells proliferate in many organ systems of the mother, such as the brain, and remain there for her entire life. Furthermore, stem cells from the mother traverse the placenta and implant into various tissues of the fetus...The continued presence of these fetal cells in a woman after she gives birth may have health benefits and risks. Dr. Lee Nelson of the Fred Hutchinson Cancer Research Center assessed the number of male fetal cells in autopsied brains of women who died between the ages of 32 and 101. His research uncovered a clinical association—those women who were diagnosed with Alzheimer’s disease had significantly less male fetal stem cells in their brains than women who did not have the disease. This study suggests that the presence of fetal stem cells in a woman exerts a lifelong protective effect for Alzheimer’s disease. In other studies, evidence is presented that shows how fetal cells present in a pregnant woman are capable of accelerating repair of damaged heart tissue and pancreas, thereby providing protective benefits to the woman against heart disease and type-1 diabetes. There are also health risks resulting from fetal cells implanting into various tissues of a pregnant woman. Several studies have shown that the presence of fetal cells in women was strongly associated with a lifelong reduced risk of developing breast cancer but an increased risk of developing colon cancer.

The debate up to now has been based on the discussion and elucidation of sources in the rabbinic literature – not on scientific evidence. Prior to [Rabbi Dr. Tendler and Dr. Loike’s] paper [1], no one claimed that scientific evidence was the basis for the halachic debate. Therefore, it does not make sense to claim that new evidence can influence one or other of the sides of this debate.

The Gaon R' Shlomo Zalman Auerbach wrote to me that in his opinion this act should not be done in the first place because it would cause confusion and uncertainty, and this is not the view of the Torah. And if this has already been done, to the question of who is called the mother of the child, the Gaon zt"l told me that although the great sages of the generation (cited above) discussed the question of the surrogate on the basis of logic and also based on the legends of the Sages, in his opinion there is no clear evidence to decide who is the mother - the woman from whom the egg was taken or the surrogate. However, according to his logic the surrogate is the mother, but it should be examined, if it is the case that a normal embryo is removed from a woman and implanted in the womb of a surrogate who will give birth to it at the end of nine months, will the ruling also be the same in such a case, and if so, from when, before forty days, before the completion of three months or even at the beginning of the ninth month. Therefore, it seems to him that in all these questions concerning Torah law, we need to be strict. And if the surrogate is a non-Jew, the child will have to convert out of doubt. On the other hand, if the non-Jew surrogate immersed for the purpose of conversion during her "pregnancy," this also does not benefit the fetus, because she is not its mother and has no ownership over it, and is similar to a nurse who received a child on trust...

Rabbi Shlomo Zalman Auerbach is famously quoted as saying that he found a source in the voluminous rabbinic literature

for every question that was posed to him, including all medical and technological advances, barring one: namely, the question

of determining motherhood in a surrogacy case.