When a woman conceives and gives birth to a male…[1]
Chazal’s comment is well known, but little understood. “When a woman emits seed first, she gives birth to a male. When the male emits seed first, his wife gives birth to a female.”[2] Why should this be? Why should it be the woman who determines the birth of a male baby, and her husband the opposite? And why is this the introduction to the next verses, which deal with the mitzvah of milah?
There are mitzvos that are the exclusive province of women (e.g. the counting of days of the zavah; the korban of a woman who gives birth), and there are mitzvos that are only practiced by men. The Torah wished that everyone should be able to share in the reward for all mitzvos. One way this can happen is through one’s children. The good deeds of a child confer merit to his/her parents.
A small number of time-bound mitzvos are obligatory only upon men. Hashem compensated a woman for this by giving her an outsize portion of the merit of her male offspring. Because she was responsible to a greater extent than her partner in creating her son, she is entitled to a larger portion of the parental credit. Similarly, Hashem arranged that it would be the husband who has a larger role in the creation of his daughter, and therefore enjoys more of the merit of the mitzvos that she will perform.
The mitzvah of bris milah is primarily incumbent upon a father. He is instructed to perform the circumcision, and not his wife. The Torah so instructs in order to restore a bit of parity between spouses in this hugely important mitzvah. After all, the effects of the milah stay with a person every day of his life, and remain a constant source of merit. Were the usual “rules” to apply, the mother would receive the larger share of parental merit for this mitzvah throughout the life of her sons. Hashem evens the score somewhat by making the father the sole authorized agent to perform the mitzvah, which grants him a larger share than he would otherwise be entitled to.
Chazal[3] teach that the Torah saw potential incompatibility of the simcha that everyone feels at the bris of a baby, with her forced post-partum separation from her husband. Therefore, the Torah reduced the fourteen days of tumah after the birth of a daughter to only seven in the case of a son. This would allow her to feel abundant joy at her return to her husband. According to our approach, however, there is an additional reason for her simcha on the day of the bris: because of her greater role in the creation of her son, she has a greater share in the mitzvah of milah, and all its continuing merit.
The says of HaKadosh Baruch Hu are indeed just – and finely tuned.