Egg Donation in Light of Halacha

Hello, a respectful greeting. Your question is actually composed of several questions, and I will try, with Hashem's help, to answer them all. 

A. Regarding maternity in the case of egg donation, the view of the vast majority of the poskim of our generation, may they live and be well, is indeed that the woman who provided the egg is the full mother of the newborn. 

B. However, there are opinions that the surrogate is also considered the mother, so that according to them the newborn has two mothers. 

C. There is also one who maintains that there is doubt whether the woman who provided the egg is considered the mother or the surrogate. Therefore, in any case where there is such doubt in a matter involving the laws of the Torah, one must act stringently. Thus, if the surrogate is a non-Jewish woman, the child will have to undergo conversion out of doubt. On the other hand, if the surrogate immersed for the sake of conversion during her pregnancy, that also does not help the fetus, because perhaps she is not its mother and has no ownership over it, and it is comparable to a wet nurse who received a child as a deposit. 

D. There is a solitary opinion that only the surrogate is the mother. But even according to this view, if the woman who provided the egg is non-Jewish, the newborn would require full conversion, and if the woman who provided the egg is a mamzeret, heaven forfend, the status of mamzerut passes to the newborn. 

E. In practice, it is severely prohibited to become pregnant from an egg that comes from a Jewish donor, just as it is prohibited for a man who married a woman and fathered children in one country to go afterward and marry a woman in another country, lest in the future a brother marry his sister out of lack of knowledge, and the earth be filled with immorality. 

F. Becoming pregnant from an egg that comes from a reservoir called an egg bank is prohibited even more, because this causes a serious practical question regarding the child’s fitness for marriage, since it is impossible to know whether the egg donor was a mamzeret or not. In practice, if this was already done, there are poskim who permit the child to marry after the fact (Responsa Yabia Omer, volume 10, Even HaEzer, Siman י), and there are those who invalidate even after the fact (Responsa She'erit Yosef, Even HaEzer, סימן עט, and Responsa Briti Shalom, volume 4, סימן יד, based on the words of Rabbi Yosef Shalom Elyashiv, of blessed memory, in Kovetz Teshuvot). 

G. The only permitted way according to halacha is to receive an egg donation from a non-Jewish woman. And of course, after the birth, the child must be immersed for the sake of conversion in the presence of three observant men. If it is a boy, they must intend at the time of the circumcision that the brit is being performed for the sake of conversion, and this must be in the presence of three observant men who are aware of it. If it is a girl, one must know that she will be forbidden to marry a kohen, as explained in Shulchan Aruch, Even HaEzer, סימן ו, סעיף ח, that a convert, even if she converted before the age of three, is forbidden to a kohen. 

Sources: A. Rabbi Ovadia Yosef, of blessed memory (Responsa Shema Shlomo, volume 8, Even HaEzer, end of סימן ג, בשם his son Rabbi David Yosef, may he live and be well, who instructed him כך twice. The same is found in Rabbi Ovadia Yosef's handwritten responsa dated 8 Shevat 5772 and 12 Kislev 5773, published in Kovetz Mishnat Yosef, Tishrei 5775, pages תה, תז-תח. Therefore, although there are testimonies that he did not hold this way in the past, his later position on this matter was the letters in his own handwriting from the years 5772 and 5773, in the very last period of his life. And the accepted halachic principle is that the later view is primary). Also of this opinion are Rabbi Yitzchak Rosental, of blessed memory (Mishnat Yaakov on Erakhin and Hekdeshot, chapter 1, halacha 13), Rabbi Shalom Mashash Amar, may he live and be well (Responsa Shema Shlomo, volume 8, Even HaEzer, סימנים א-ג), Rabbi Yechia Tubul, may he live and be well, Av Beit Din of Lyon (Mareh Yesharim on Tractate Yevamot, סימן לז), Rabbi Pinchas Shapira, may he live and be well (Responsa Briti Shalom, volume 4, סימן טו), and others. B. See Responsa Briti Shalom (there) for a clear and reasoned explanation of the dispute. C. Nishmat Avraham, Even HaEzer, page לה, בשם Rabbi Shlomo Zalman Auerbach, of blessed memory. See also the above-mentioned Kovetz Mishnat Yosef (page תח) in Rabbi Ovadia Yosef's responsum, that although a child born to a non-Jewish woman from a Jewish egg is considered Jewish and should be circumcised with the blessings as usual, nevertheless it is very good to advise the parents to immerse him for the sake of conversion. D. Rabbi Avraham Yitzchak Waldinberg, of blessed memory, in Responsa Tzitz Eliezer, volume 19, סימן מ. See also Responsa Briti Shalom, volume 4, סימן יד, which explains why even according to this view the disqualification of the egg donor passes to the newborn. E. Tractate Yevamot (37b), and this is ruled as halacha in Shulchan Aruch, Even HaEzer, סימן ב, סעיף יא. For this reason, in Responsa Yabia Omer, volume 2, Even HaEzer, end of סימן א, it was written to forbid receiving sperm donation from another man. Apply the same reasoning here. With great success, Hillel Meirs