Leviticus 20:17-18

17‘1If there is a man who takes his sister, his father’s daughter or his mother’s daughter, so that he sees her nakedness and she sees his nakedness, it is a disgrace; and they shall be cut off in the sight of the sons of their people. He has uncovered his sister’s nakedness; he bears his guilt.

182If there is a man who sleeps with a menstruous woman and uncovers her nakedness, he has exposed her flow, and she has uncovered the flow of her blood; so both of them shall be cut off from among their people.