Leviticus 21:2-4

New King James Version

² except for his relatives who are nearest to him: his mother, his father, his son, his daughter, and his brother; ³ also his virgin sister who is near to him, who has had no husband, for her he may defile himself. ⁴ Otherwise he shall not defile himself, being a ^[a]chief man among his people, to profane himself.