The Sin-Offering of the Mother
"When the days of her purification have been completed, whether for a son or for a daughter, she shall bring a sheep in its first year as a burnt offering, and a young dove or a turtle dove as a sin offering, to the entrance of the Tent of Meeting, to the kohen. (VaYikra 12:6).
In simple terms: after bearing a child, a woman must bring a sin-offering (Korban Chatat) and a burnt-offering (Korban Olah).
We can understand the need for a Korban Olah. The woman must show her gratitude to God for granting her the ability to bring life into the world. However, why the sin-offering? What sin has she done? On the contrary, she has obeyed humanity's very first commandment (See Bereshit 1:28). This issue needs explaining.
This question also bothered the Rabbis. Rabbi Shimon bar Yochai explains: "When she kneels in bearing she swears impetuously that she will have no intercourse with her husband" (Niddah 31b).
Essentially, labor is so painful that during the experience the woman will swear that she will never again be intimate with her husband. However, since she will eventually be with her husband again, she has sworn falsely and therefore, has sinned.
This answer is difficult to accept for a number of reasons. Firstly, there are surely many women that do not make this oath. Secondly, the Torah commands the bringing of the sacrifice as part of her purification process, irrespective of whether she has committed this sin or not. And finally, as Rabbi Yoseph points out, the expiation for false oaths is an "asham" not a "chatat".
Modern scholars have suggested that our problem with this law is based upon our mistranslation of the Hebrew word: "חטא" (sin) and because of our lack of understanding of ancient culture.
The ancients were anxious over the state of "tuma" - "impurity". Being impure was like walking a tight rope; one tiny slip and you fall into the abyss of sin, risking G-d's wrath. Therefore, being impure necessitated varying levels of restrictions and eventually purification, which resulted in resuming a normal life.
While we in the modern world take childbirth for granted, it is actually a very dangerous time for both the infant and the mother. Mortality rates for newborns and their mothers were very high in the ancient world.
The release of blood as well as the pain and any complication at childbirth were life threatening. Being close to death, the mother was automatically impure. Upon recovering, the mother needed to return to normalcy. This was cdone by expiating the "tumah", i.e through purification.
The Korban Chatat is a purification offering, not a sin offering. It also purifies the sinner from sin and that was its major purpose. Indeed, the word "chet" means "impure" as well as "sin". This we can show by examining the use of "chet" when it appears as its antonym.
"To cleanse (לחטא) the house, he shall take two birds ..." (ibid 14:9)
"He shall [thus] cleanse (וחטא) the house with the blood of the bird, the spring water..." (ibid 52)
In these instances (and in many others), the verb means: "cleanse" or "purify". Therefore, in its regular form it "unclean" or "impure".
When seen in this manner, we can understand why the mother needs to bring the Korban Chatat. She needs to shake off the dangerous "tuma" that has enveloped her. She does that by bring a Chatat; a purification offering.