Leviticus 12:7-8

7He is to present it before Adonai and make atonement for her. Then she will be cleansed from the discharge of her blood. This is the Torah for her who gives birth, whether to a male or a female child.

8If she cannot afford a lamb, then she is to bring two turtledoves or two young pigeons, one for a burnt offering and the other for a sin offering. Then the kohen will make atonement for her, and she will be clean.”