Leviticus 15:30

And the priest shall offer the one for a sin offering, and the other for a burnt offering; and the priest shall make an atonement for her before the Lord for the issue of her uncleanness.

Cross-reference

Leviticus 15:14 applies the same bird offering to a man, emphasizing the parallel structure of purification for both genders.

Leviticus 5:7 also describes two birds used as a sin and burnt offering for a trespass, matching the pattern here.