(יא) מותר אדם בבת אשת אביו שיש לה מאיש אחר אפילו חורגה (פי' בת אשת אב) הגדלה בבית בין האחין מותרת להם ולא חיישינן למראית העין שנראית כאחותם:
(11) A man is permitted to [marry] the daughter of his father's wife that she has from another man [i.e. his stepsister]. Even if she grew up in the house among the brothers [i.e. her stepbrothers] she is permitted to them, and we are not afraid of marit ha'ayin [an action that appears to be sinful] of people thinking that she is their sister.
R' Shlomo Brody, Ask the Rabi, Jerusalem Post 5/2/13
Many decisors, such as Rabbi Shmuel Wosner, believe that any form of egg donation or gestational pregnancy remains prohibited because it causes confusion about personal lineages and leads to multiple health and moral concerns. Other figures believe that it may be permissible when other fertility options have failed, even as they too remain concerned with its potential social implications and demand strict regulation of the process.
Although many doctors prefer that the host mother should have previously had successful pregnancies, most Jewish scholars insist that the mother should not be married, thereby preventing additional questions regarding infidelity. Yet in a well-publicized case in 2006, Israeli Chief Rabbi Shlomo Amar allowed, with much controversy, a married woman to volunteer as a host mother for an impoverished couple who had suffered several miscarriages and could not afford to hire a surrogate mother.
תנו רבנן שלשה שותפין יש באדם הקב"ה ואביו ואמו אביו מזריע הלובן שממנו עצמות וגידים וצפרנים ומוח שבראשו ולובן שבעין אמו מזרעת אודם שממנו עור ובשר ושערות ושחור שבעין והקב"ה נותן בו רוח ונשמה וקלסתר פנים וראיית העין ושמיעת האוזן ודבור פה והלוך רגלים ובינה והשכל
The Rabbis taught in a Braita: There are three partners in the creation of a person: the Holy One, blessed be He, the father, and the mother. The father seeds the white substance (semen) from which the bones, sinew, nails, brain, and white of the eye are formed. The mother seeds the red substance from which the skin, flesh, hair, and black and white of the eye are formed. And the Holy One, blessed be He, places in him the spirit of life, the soul, the facial countenance, eyesight, hearing, the power of speech and walking, and insight and understanding.
מתיב רבא לפיכך גר וגיורת צריכין להמתין ג' חדשים הכא מאי להבחין איכא ה"נ איכא להבחין בין זרע שנזרע בקדושה לזרע שלא נזרע בקדושה
Rava challenged it from a Braita, which states: Because of this decree, a male convert and a female convert who are married prior to their conversion must wait 3 months after the conversion before resuming relations so that we will know whether she was pregnant prior to the conversion. Now, if the purpose of the decree is to distinguish between the offspring of the first husband and that of the second, it should not apply in this case for here, what is there to distinguish between? She was married to the same man both before and after the conversion. The Gemara answers, here too, in the case of converts it is necessary to distinguish between offspring that was conceived in sanctity and offspring that was not conceived in sanctity.
The well-known story of Yosef and Dina's in-utero transfer is widely suggested as a definative source establishing the birth-mother as the halachic mother. However, as illustrated below this is far from the case.
Targum Yonatan comments that Leah’s prayers to Hashem that Rachel bear a male child where answered. Miraculously, the male and female fetuses in Leah and Rachel’s wombs respectively switched locations. Yosef, whose conception occurred within Leah, was born to Rachel; and Dina, who was conceived from Rachel, was born to Leah. This episode also appears in the commentary of Da’at Zekanim and in the litergical poems of Rosh Hashanah. In addition, it is also reported by the Maharsha (Masechet Niddah 31a) in the name of Sefer Panach Raza.
The miraculous fetal exchange of Yosef and Dina would appear to be a direct parallel to our modern dilemma of maternal identity in surrogacy. Since the Torah refers to Dina as the daughter of Leah, it could be argued that this proves that birth, and birth alone, determines maternity. Indeed, the Torah is replete with references to Yosef as Rachel’s son and never as a child to Leah. This proof is further significant in that it establishes the birth mother as the halachic mother even when conception and partial gestation occurred in another host.
However, not all commentators understood the implications of this episode uniformly. The Tur, in his commentary to the Torah (Breishit 46:10), asks how Shimon was permitted to marry Dina, since even Noahide law prohibits marriage to a sister of the same mother. (Shaul ben ha'kenaanit is listed among Shimon’s children who decended to Egypt with Yaakov. The midrash identifies the Canaanite as a euphamism for Dina who was violated by Sh’chem.) He answers that since Dina was conceived in Rachel’s womb, she was in actuality Rachel’s daughter. Therefore, Shimon and Dina were only paternal siblings and did not share a common mother. According to the Tur, birth is not the determinant of maternity. Rather some earlier event, shared by Dina and Rachel, creates that maternal bond.
Rabbi Moshe Sternbach (Teshuvot Ve'hanhagot) rejects adducing any proof from the story of Yosef and Dina on the grounds that "Ein Lemaidim Mima'ase nisim". He suggests the possibility that Dina not only physically transferred to Leah’s womb, but miraculously acquired her genotype as well. Therefore, Leah is both the genetic and birth mother of Dina and no comparison to surrogacy can be made.
An additional approach to understanding this episode is based on the plain meaning of the Gemara Berachot 60a. The gemara discusses whether it is appropriate to beseach G-d for a male or female child once his wife is already pregnant. Alternatively, such a request constitues a prayer in vain--tefilat shav, since what is done is already done. In support of such requests, the gemara states that after Leah’s prayers on behalf of Rachel the male fetus within her womb transformed into a female, while the female fetus in Rachel became a male. Apparently, this refers to a metamophasis, rather than an actual fetal exchange. Taking this approach neutralizes any inference from the circustances surrounding Yosef and Dina’s births regarding the determinant of maternal identity.
וא"ל אנטונינוס לרבי נשמה מאימתי ניתנה באדם משעת פקידה או משעת יצירה א"ל משעת יצירה א"ל אפשר חתיכה של בשר עומדת שלשה ימים בלא מלח ואינה מסרחת אלא משעת פקידה אמר רבי דבר זה למדני אנטונינוס ומקרא מסייעו שנאמר (איוב י, יב) ופקודתך שמרה רוחי
And Antoninos said to Rabbi Yehuda HaNasi: From when is the soul placed in a person? Is it from the moment of conception or from the moment of the formation of the embryo, forty days after conception? Rabbi Yehuda HaNasi said to him: It is from the moment of the formation of the embryo. Antoninos said to him: That is inconceivable. Is it possible that a piece of meat could stand for even three days without salt as a preservative and would not rot? The embryo could not exist for forty days without a soul. Rather, the soul is placed in man from the moment of conception. Rabbi Yehuda HaNasi said: Antoninos taught me this matter, and there is a verse that supports him, as it is stated: “And Your Providence [pekudatekha] has preserved my spirit” (Job 10:12) indicating that it is from the moment of conception [pekida] that the soul is preserved within a person.
ת"ש שני אחים תאומים גרים וכן משוחררים לא חולצין ולא מייבמין ואין חייבין משום אשת אח היתה הורתן שלא בקדושה ולידתן בקדושה לא חולצין ולא מייבמין אבל חייבין משום אשת אח היתה הורתן ולידתן בקדושה הרי הן כישראלים לכל דבריהן
Come and learn, two brother twin converts and so too freed slaves they do not perform Chalitzah and not Yevamah and are not liable due to sleeping with the others wife (post-marriage). If their conception was before conversion and their birth afterward they do not perform Chalitzah and not Yevamah and but are liable due to sleeping with the others wife (post-marriage). If conception and birth was after conversion, they are Israelites for all matters.
(ז) וַיְהִ֨י אֹמֵ֜ן אֶת־הֲדַסָּ֗ה הִ֤יא אֶסְתֵּר֙ בַּת־דֹּד֔וֹ כִּ֛י אֵ֥ין לָ֖הּ אָ֣ב וָאֵ֑ם וְהַנַּעֲרָ֤ה יְפַת־תֹּ֙אַר֙ וְטוֹבַ֣ת מַרְאֶ֔ה וּבְמ֤וֹת אָבִ֙יהָ֙ וְאִמָּ֔הּ לְקָחָ֧הּ מָרְדֳּכַ֛י ל֖וֹ לְבַֽת׃
(7) And he brought up Hadassah, that is, Esther, his uncle’s daughter; for she had neither father nor mother, and the maiden was of beautiful form and fair to look on; and when her father and mother were dead, Mordecai took her for his own daughter.
כי אין לה אב ואם ובמות אביה ואמה למה לי אמר רב אחא עיברתה מת אביה ילדתה מתה אמה ובמות אביה ואמה לקחה מרדכי לו לבת
“For she had neither father nor mother…And when her father and mother died” (Esther 2:7). Why did it need to say this again? Aha said: When her mother became pregnant with her, her father died; when she was born, her mother died. “And when her father and mother died, Mordecai took her for his own daughter” (Esther 2:7)
וכשילדתה אמה מתה - ולא נראית לקרות אם:
And when she was born her mother died - and it was not seen to call her mother.
ואי מיעברא עד ארבעים מיא בעלמא היא
And if she is pregnant, until forty days from conception the fetus is merely water. (It is not yet considered a living being, and therefore it does not disqualify its mother from partaking of teruma.)
"Medical-Halachic Decisions of Rabbi Shlomo Zalman Auerbach" by Dr. Avraham Steinberg
Rabbi Auerbach opposes surrogate motherhood a priori. If, however it was performed, both the genetic mother (i.e. egg donor) and the birth mother are considered mothers for Halachic purposes. If either the surrogate mother or the genetic mother is non-Jewish, the child must undergo full conversion to Judaism, even if the surrogate mother herself converted during the pregnancy.