The Gemara in Yevamos (22a, 97b) informs us that one who converts is no longer considered to be related to his prior relatives because of the principle of “Ger Shenisgayer K’katan Shenolad Dami” (one who converts is akin to a newborn child). Based on this, a ger may (at least m’doraisa) give testimony in a court for or against a “relative” such as a brother, and there are also no Biblical prohibitions of incest with any of the former family members. However, in Yevamos 98a, the Gemara invokes another principle: “Ein Av L’Mitzri” (A “Mitzri” [generic title for gentile in this context] is not considered to have a father), based on the verse “Zirmas Susim Zirmasam”. In the context in which the Gemara brings it, “Ein Av L’Mitzri” seems to be utilized specifically to explain why a convert has no Halachic paternal relatives. This, however, begs the question: why is such a principle necessary if the more general axiom of “Ger Shenisgayer K’katan Shenolad Dami” already teaches us that a convert has no relatives from his past?

Tosfos in Bechoros (46a s.v. Nisgayirah) are bothered by this question, and they conclude that “Ein Av L’Mitzri” is only necessary to explain why Chazal don’t treat paternal family members as relatives on a Rabbinic level, the way they did with some maternal relatives. (See also the Ramban [Yevamos 98a], who maintains that we derive from “Ein Av L’Mitzri” that gentiles who have not converted are generally permitted to marry their paternal relatives.)

Rashi, however, deals with the need for “Ein Av L’mitzri” in an entirely different way. He comments (Yevamos 98a s.v. Ha) that this rule explains why there is no relationship between a convert and his prior paternal family even where the principle of “Ger Shenisgayer K’katan Shenolad Dami” wouldn’t apply, which happens in a case of horaso shelo bikdusha v’laidaso bikdusha – a child who converted in utero. This is consistent with Rashi in Bechoros (46a s.v. Nisgayirah), where he invokes only “Zirmas Susim Zirmasam” as the source that one whose mother converts while pregnant does not inherit his father. 1 Rashi presumably understands that 1)one who converts in utero is not considered to have undergone an independent conversion process, and that 2)one becomes “k’katan shenolad” specifically by going through that process.

This understanding of Rashi leads to a number of interesting conclusions, both practical and conceptual.

1) Perhaps most strikingly, Rashi should maintain that if a Jewish man impregnates a non-Jewish woman and the mother then converts while still pregnant, the child would be considered fully related to his father, even though he was not Jewish at the time of conception! After all, he is not “K’katan Shenolad” (having converted in utero), nor is the rule “Ein Av L’Mitzri” applicable (since his father is Jewish).

2) Rashi’s assumption, that the conversion process of an embryo is not an independent one , seems to be dependent on the debate as to whether or not we maintain ubar yerech imo- that an embryo is considered to be part of its mother’s body (see Yevamos 78a). This leads us to one of two conclusions. Either Rashi understands that the entire sugya in Yevamos 97b-98a accepts the position of ubar yerech imo, notwithstanding that it is an unresolved debate in various places. (See Tosfos in Sanhedrin 80b s.v. Ubar for a dispute about what is the primary opinion. Admittedly, Rava is the amora in Yevamos who introduces Ein Av L’Mitzri, and in Temura (30b) Rava apparently believes that ubar yerech imo.) Alternatively, Rashi might believe that even according to the opinion that ubar lav yerech imo, we don’t consider the conversion to be a process performed entirely independently by the embryo. There is some evidence for such an approach from Tosfos in Kesuvos 11a (s.v. Matbilin), where they suggest that even if a child cannot convert Biblically since he can neither make his own decision nor appoint a proxy, an embryo can be converted, and they make no mention of the issue of ubar yerech imo (see R’ Akiva Eiger’s comment on that Tosfos as well as the essay of R’ Naftoli Trop.) The Gemara in Yevamos 78a would then have to be reevaluated in this light.

3) Finally, the Gemara makes it clear that a converted embryo, upon birth, is considered a full-fledged relative of his mother and all siblings of his from his mother who are either in utero with him or born subsequently. Some contemporary poskim deduce from this that giving birth creates motherhood even without conception, since the mother and embryo converted after conception and therefore they are not related based their original status. This obviously has repercussions for the questions of surrogate motherhood and egg implantation. However, according to Rashi, there seems to be no evidence whatsoever. Since “Ger Shenisgayer K’katan Shenolad Dami” does not apply in this case, and the only reason he is not related to his father is Ein Av L’mitzri, it should follow that to his mother he is in fact related, potentially even based on conception.