The sins of childbirth?

Edit: We discussed this in class and it was very enlightening. I no longer have the questions that I had upon reading it the first time.

There's no school this week (none last week either) because of Ike, so I'm doing my best to stay caught up on all the readings from the last 2 weeks. Today I'm reading next week's assignment from the old testament: Leviticus, Numbers & Deuteronomy. I just came across this passage and it's troubling me.

Leviticus 12
Purification After Childbirth

1 The LORD said to Moses, 2 "Say to the Israelites: 'A woman who becomes pregnant and gives birth to a son will be ceremonially unclean for seven days, just as she is unclean during her monthly period. 3 On the eighth day the boy is to be circumcised. 4 Then the woman must wait thirty-three days to be purified from her bleeding. She must not touch anything sacred or go to the sanctuary until the days of her purification are over. 5 If she gives birth to a daughter, for two weeks the woman will be unclean, as during her period. Then she must wait sixty-six days to be purified from her bleeding.

6 " 'When the days of her purification for a son or daughter are over, she is to bring to the priest at the entrance to the Tent of Meeting a year-old lamb for a burnt offering and a young pigeon or a dove for a sin offering. 7 He shall offer them before the LORD to make atonement for her, and then she will be ceremonially clean from her flow of blood.

" 'These are the regulations for the woman who gives birth to a boy or a girl. 8 If she cannot afford a lamb, she is to bring two doves or two young pigeons, one for a burnt offering and the other for a sin offering. In this way the priest will make atonement for her, and she will be clean.' "

Okay, first of all, I realize that I need to take this text in context - it comes from ancient times when the culture was very different. Never the less, I think it's fair to point out when something about the reading troubles me.

...I guess my issue is that up until now, all of the "sins" and "uncleanly" issues involve actions that humans take, mistakes they make, wrongs they perform against God or their neighbor. But this... childbirth is natural. And if it was just a matter of a woman remaining "unclean", I would be able to pass it off as, culturally, in those times, women gave birth away from camp so that the blood didn't contaminate the camp. But at the end, it actually implies that she has sinned. Sinned? By giving birth? Excuse me? "Forgive me lord, for I have sinned - I have given my husband a son"?!

So, that's my issue. Now I'm going to set it asside and continue reading.