Leviticus 20:19-21

20:19 You must not expose the nakedness of your mother’s sister and your father’s sister, for such a person has laid bare his own close relative. They must bear their punishment for iniquity. 20:20 If a man has sexual intercourse with his aunt, he has exposed his uncle’s nakedness; they must bear responsibility for their sin, they will die childless. 20:21 If a man has sexual intercourse with his brother’s wife, it is indecency. He has exposed his brother’s nakedness; they will be childless.