The first is why a woman who has given birth is ritually impure and needs to bring an offering. Is not procreation the very first of the commandments? Are not children “a heritage from the Lord” (Psalm 127:3)? Is not a mother fulfilling a God-given purpose?
Abravanel suggests the offering is not because of any sin but in thanksgiving to God who brought her safely through the pain and danger of childbirth. Not only for herself should she be grateful, but on behalf of the child; Rabbi Abba bar Kahana remarks in the Midrash, “The embryo dwells in its mother’s womb and the Holy One, blessed be He, watches over it that it does not fall and die. Does this not warrant praise?”
Another Midrash speaks of the wonder of childbirth and the beneficence of the Almighty. Rabbi Levi says, “The way of the world is that if someone secretly leaves a purse of silver with another person, and the latter gives back a pound of gold in public, should he not be grateful? Thus it is with the Holy One, blessed be He. Human beings secretly deposit with Him a drop of fluid, and the Holy One, blessed be He, gives back magnificent, complete human beings in public. Does this not warrant praise?”
The mother’s ritual impurity is seven days for a boy and 14 for a girl. Some commentators believe it takes longer to recover from the birth of a girl; a medical view on this assertion would be interesting. Samson Raphael Hirsch thinks the second seven days in the case of a girl takes the place of the milah of a boy, who is circumcised after the first week of life.