One of the more difficult comes at the beginning of the sidra (Lev. 12:2), where we hear that if a woman has a male child she is t’me’ah (ritually impure) for seven days but if it is a girl she is t’me’ah for 14 days.
Two questions arise: why does childbirth make her ritually impure at all, and why is there a difference between the birth of a boy and a girl?
The first question implies a paradox. How can a woman who has brought joy into the world become even temporarily ritually impure?
The answer has to do with her role in procreation. Literally, physically, she is a partner with God in the creation of the world. When she menstruates, her potential for creation has not been realised that month and she has temporarily lost an opportunity of spiritual significance. After childbirth, her further creative potential is postponed for a short time.
If she has given birth to a boy, her achievement is in a sense less spiritually significant than if she has a girl, as the baby girl brings her own creative potential into the world.