Leviticus 20:20
And if a man has sex relations with the wife of his father's brother, he has put shame on his father's brother: their sin will be on them; till the day of their death they will have no children.And if a man has sex relations with the wife of his father's brother, he has put shame on his father's brother: their sin will be on them; till the day of their death they will have no children.