The woman with an irregular discharge shall bring an offering after purification

That is that He commanded us that any woman who is healed from a discharge offer a sacrifice - and that is two turtledoves or two young pigeons. And this is the sacrifice of the zavah; and she is lacking [full] atonement until she offers it. And perhaps the questioner will challenge me and say, "Since the sacrifice of the zav is like the sacrifice of the zavah, why don't you [just] count the type of sacrifice that one is obligated, regardless of who is obligated - like you did with the sacrifice of the sin-offering, the definite guilt-offering, the uncertain guilt-offering and the variable sacrifice? As you counted each and every one as only one commandment, each; and you did not concern yourself with the multiplicity of transgressions for which one is liable, such that one is liable a sacrifice for each and every one of them. So it would have been appropriate for you not to concern yourself with the multiplicity of [classes of] people that are liable for the fowl offering!" That questioner should know that the sacrifices of the zav and the zavah are not for sins, but rather for a specific matter. And if the matter of discharge were the same in men and women, like the name is the same - as the name of one is zav and the name of the other is zavah - it would have then been appropriate to count them as one. But the matter is not like this. For the displacement of blood in a woman - if blood would [likewise] be displaced in a man, he would not be liable for a sacrifice. And the word, zivut, relates to the matter of displacement. But the displacement is not the same in both of them. So in the explanation (Niddah 32b), they said, "A man becomes impure with white, and a woman with red." And the law of the zav and the zavah is not like the law of a man with tsaraat and a woman with tsaraat. And the open proof about this is their saying in Keritiot (Keritiot 8b), "Four are lacking [full] atonement: The zav; the zavah; the woman after childbirth; and one with tsaraat." Behold you see how they counted the zav and the zavah as two, but counted tsaraat as one - whether it is a man or a woman. For the discharge of a man is different than the discharge of a woman. And the verse that appears about this matter is His saying, "When she becomes clean of her discharge [...]. On the eighth day she shall take two turtledoves or two pigeons" (Leviticus 15:28-29). (See Parashat Metzora; Mishneh Torah, Offerings for Those with Incomplete Atonement 1-3.)