Parasha Tazria’-Metzora’– *תזריע -מצורע*
A woman who gives seed and gives birth to a boy,… she will be impure 7 days. …if she gives birth to a girl, she will be impure 14 days.
The more a person is holy, the more impurity they attract. Thus a woman, becomes more impure when she gives birth to a girl. A woman who conceives the people of the Jewish nation is of great importance to Hash-m. Thus the woman who gives birth to another “creator” has more holiness and thus more potential for impurity.
Her role as a mother or potential mother makes her precious to Hash-m.
This is one reason for the laws of Tzniut / Modesty for women. We don’t publicize the amount of money or jewelry we have. Things that are precious we hide. Thus a Jewish daughter, precious in the eyes of Hash-m, Hashem thus asks them to dress modestly.