Traditionally, firstborn males have observed the fast of the firstborn on the Eve of Passover either by fasting or by participating in a siyyum or another se’udat mitzvah, where the obligation to eat or be part of the simcha overides the fast. The original source for the fast in Tractate Soferim does not specify the reason for the fast, or whether the fast is limited to males. The Vilna Gaon, the Mishnah Berurah and the Arukh Hashulhan all point out that there are two possible reasons for the fast–either because the Israelite firstborn were saved in Egypt or because of the particular holiness of firstborn males. They indicate that if the former reason is correct, it is equally applicable to women, since women were also included in the miracle in Egypt, while if the latter reason is correct, women would not have to fast. The assumption that women were also saved is based on the midrash that relates that Bitya, daughter of Pharaoh, was spared in the merit of Moshe, thereby implying that other female Egyptian firstborn were killed. The Shulhan Arukh therefore writes: “v’yesh she’omer she’afilu nekeiva bekhora mitaneh” (and some say that even a women fasts if she is a firstborn–siman 470, se’if 1). This is also the view of later Sephardi authorities (see haggadah of the contemporary Sephardi authority, R Ovadiah Yosef who adds leniencies for women who are pregnant or nursing, but says that if a firstborn woman can attend a siyyum without too much trouble she should do so). The Maharil and the Bach went further, saying that women should fast or go to a siyyum. Nevertheless, the primary Ashkenazi authority of the sixteenth century, the Rema, writes “ein haminhag ken” (this is not the custom). While this is endorsed by some other authorities, it might be that attending a siyyum on Erev Pesach is a custom that firstborn women today should adopt since many sources believe that women logically should have as much of an obligation to fast as men.
It is interesting that while the Rema stated that it was not the custom for firstborn women to fast, he considered that a woman should fast instead of her young firstborn son if the father is also a firstborn. The rationale is that the father’s fast is for himself, and cannot fulfill his son’s obligation as well as his own. The Mishnah Berurah, noting that some authorities disagree and hold that the father’s fast can fulfill the son’s responsibility as well, advises that when it is very difficult for a woman to fast, there is room to be lenient and allow her not to fast. Thus it would seem that nowadays when the general practice is to attend a siyyum and not to fast, that a mother of a firstborn child whose father is also a firstborn should go to a siyyum on behalf of her child.
JOFA is grateful to Samuel Groner for sharing his sources and research on this topic.