In this week’s parshah, Pharaoh’s daughter finds a baby in a basket in the Nile River and saves its life. The baby turns out to be none other than Moshe Rabbenu. Since he was crying, Pharaoh’s daughter attempted to have him nurse from several Egyptian women, but Moshe refused. Moshe’s sister Miriam then offered to have a Jewish woman nurse the baby. When Pharaoh’s daughter agreed, Miriam brought Moshe’s mother, who nursed her son.
The Midrash Rabba asks why Moshe refused to nurse from an Egyptian woman when one may do so according to halacha (Avoda Zara 26a). The Midrash answers that Hashem said, “Should a mouth destined to speak with Me nurse from a tamei source?” The Gemara (Sotah 12b) offers the same answer but attributes this rhetorical question to Moshe (although some emend the text of the Gemara so that it mirrors that of the Midrash).
As mentioned, the Gemara rules that a Jewish baby may nurse from a non-Jewish woman. It also rules (Yevamos 114a) that a Jewish baby may nurse from a non-kosher animal. These two rulings lead Rabbenu Chananel to argue that a Jewish baby may nurse from a non-Jewish woman only because the life of a baby is always considered endangered without milk. It’s a case of pikuach nefesh in other words. The milk, though, is not kosher. This explanation is really the only way to understand the halacha that a baby may nurse from a non-kosher animal, whose milk is surely normally forbidden.
Other Rishonim, however, disagree. They assert that nursing from a non-Jewish woman is completely permitted and has nothing to do with pikuach nefesh. Refraining from nursing from a non-Jewish woman is merely going beyond the letter of the law.
There are two separate reasons given for not nursing from non-Jewish women despite it being permitted. Rashi (in his commentary on Sotah) and the Ritva explain that non-Jewish women eat non-kosher food which will affect a Jewish child nursing from her.
The Rashba and Meiri state that the actual milk will affect the baby. They argue that a baby shouldn’t be sustaining itself from a woman who is not Jewish and thus has a different nature than ours. One should nurse from a Jewish woman instead who will instill in the child the signature Jewish character traits of mercy (rachmanim), modesty (baishanim), and kindness (gomlei chasadim).
One practical difference between these opinions arises when one hires a non-Jewish wet nurse who refrains from eating non-kosher foods. According to Rashi and the Ritva, there is no reason for her not to nurse a Jewish baby. According to the Rashba and Meiri, however, there would still be reason to get a Jewish wet nurse instead.
In the case of a Jewish woman who is forced to eat non-kosher foods for health reasons, the Rashba and Meiri would actually be more lenient while Rashi and the Ritva would be more stringent. Even though the woman is eating these foods with the sanction of halacha, Rashi and the Ritva would maintain that the child is still being affected by the non-kosher food, which is problematic.
The Rema (Shulchan Aruch, Yoreh Deah 81:7) rules that a child should always avoid nursing from a non-Jewish woman when it is possible to nurse from a Jewish woman. The Rema quotes the Rashba’s reasoning that the nature of non-Jewish women will affect the child. The Rema also cites an opinion that a Jewish woman who is forced to eat non-kosher foods should refrain from nursing.
The following question is raised: The Gemara states that Moshe Rabbenu did not nurse from Egyptian women because he was destined to speak with the Shechinah. It seems that this Gemara is the only source for the stringency not to nurse from non-Jewish women. Why, then, would the Rema mention this stringency in the Shulchan Aruch which is meant for all Jews (as opposed to only those Jews who are destined to speak with the Shechinah)?