Well Obviously it was because women bleeding and a future of bleeding (daughter) means more days to be icky! (Sorry a bit of humor). As we know all of the Fathers rules (600+ of them) no matter how silly or odd they seemed were always for the health and benefit of the people, and or for reasons just for our flesh to fail! My 2 cents. Doing on earth as it is in heaven. I am really guessing but would say that the risk of infection would have been the issue for any reason for her to be away after giving birth. As to why double the time and double the uncleanliness for a daughter. Was the father saying that women were twice as much to clean? With Spiritual significance far and above the physical reasons? I read and re read and looked in my Thompson chain for foot notes and notes. Nothing of importance jumped out to me.
These are the old laws and purification rites of the Old Testament (as if you didn't know). They no longer apply since Christ came and sacrificed Himself on the Cross to purify us and forgive us off our sins.
The word 'unclean' is a wholly inaccurate translation; it refers to the word for menstruation, 'tuma,' which cannot be translated into English.
During menstruation, the shedding of the unfertilized egg is considered the loss of a soul, just as men are directed not to self-satisfy because the result is also loss of souls. In both cases, it is the loss of spiritual potential.
Experiencing such a loss puts one in a special spiritual state, because the soul and body are entwined. Like burial ceremonies, the ones involved are in that special spiritual state or 'tuma,'
In this case, it is telling the husband to avoid intercourse with the woman until she stops the post-partum bleeding. Why? 'Tuma' ... a particularly spiritual state after giving life...bringing another soul into the world.
Besides, childbirth stresses body and mind; it is in the family's best interests if the woman has a chance to recuperate from the ordeal.
Remember, these people were generally nomadic desert dwellers; there were no hot showers, no sterile environments. The Bible gave them rules in order to protect them, maintain their health and provide guidance and inspiration.
This part makes more sense....
Some also suggest the longer period of time in connection with the birth of a girl was because girls are usually smaller at birth, and this would allow more time for the mother’s focused care and attention on the child. As well, since sons were more prized, the longer time at home for a mother with a new born girl would force the family to bond more deeply, over a more extended period of time with the new born girl.
This too leads to the same vein of Old vs New testament view.
The New Testament teaches that any man is the head of every woman. So a baby girl is less of a result than a baby boy... Less of a gift from God or less of a gift to God and ceremonial cleaness or uncleanness under the Jewish law was related to advancement or simplicity in life's hierarchy... If your pregnancy was less fruitful then it may reflect on your actions that caused the pregnancy and your resulting status because of the pregnancy...To be less fruitful is to be closer to uncleanness just as to less good is closer to being a bit bad in God's hierarchal assessment of life...
The Entire reading.
Leviticus 12 - Cleansing After Childbirth
A. Ceremonial impurity after giving birth.
1. (1-4) When a male child is born.
Then the Lord spoke to Moses, saying, "Speak to the children of Israel, saying: 'If a woman has conceived, and borne a male child, then she shall be unclean seven days; as in the days of her customary impurity she shall be unclean. And on the eighth day the flesh of his foreskin shall be circumcised. She shall then continue in the blood of her purification thirty-three days. She shall not touch any hallowed thing, nor come into the sanctuary until the days of her purification are fulfilled.'"
a. If a woman has conceived, and borne a male child, then she shall be unclean seven days: The child was then circumcised on the eighth day, with the ceremonial uncleanness lasting an additional 33 days, for a total of 40 days of ceremonial impurity after giving birth to a male child.
b. She shall not touch any hallowed thing: The commanded time of ceremonial impurity should not be regarded as a negative attitude towards birth or child-bearing on God's part. God commands child bearing, in that man is commanded to be fruitful and multiply (Genesis 1:28), children are regarded as a gift from God (Psalm 127:3), and a woman with many kids is considered blessed (Psalm 128:3).
i. The key to understanding this ceremony is to understand the idea of original sin. As wonderful as a new baby is, God wanted it to be remembered that with every birth another sinner was brought into the world, and the woman was here symbolically responsible for bringing a new sinner into the world.
ii. Perhaps just as importantly, the time of ceremonial impurity gave the new mother a time of rest and seclusion that would she no doubt welcomed.
2. (5) When a female child is born.
But if she bears a female child, then she shall be unclean two weeks, as in her customary impurity, and she shall continue in the blood of her purification sixty-six days.
a. If she bears a female child, then she shall be unclean two weeks: The time period for each phase was double of that when giving birth to a son. For a the birth of a daughter, a woman was unclean for 14 days followed by 66 days.
b. She shall continue in the blood of her purification sixty-six days: The longer period of ceremonial uncleanness for the birth of a daughter should not be understood as a penalty. Instead, it is linked to the idea stated in the previous verses - that the time of impurity is for the symbolic responsibility of bringing other sinners into the world. When giving birth to a female, a mother brings a sinner into the world who will bring still other sinners into the world.
i. Some also suggest the longer period of time in connection with the birth of a girl was because girls are usually smaller at birth, and this would allow more time for the mother’s focused care and attention on the child. As well, since sons were more prized, the longer time at home for a mother with a new born girl would force the family to bond more deeply, over a more extended period of time with the new born girl.