Passage Leviticus 12:1
Leviticus 12:1-5 makes a mother unclean for seven days after a son, but for two weeks after a daughter. The complaint is that the birth of a girl is treated as a double defilement, which sits badly with the claim that the book comes from a just God.
“Speak to the people of Israel, saying, If a woman conceives and bears a male child, then she shall be unclean seven days. As at the time of her menstruation, she shall be unclean.
Leviticus 12:2
But if she bears a female child, then she shall be unclean two weeks, as in her menstruation. And she shall continue in the blood of her purifying for sixty-six days.
Leviticus 12:5
Source: see Credits and references (no. 3, p. 5).