CCC 2388

Incest designates intimate relations between relatives or in-laws within a degree that prohibits marriage between them.¹⁸⁰ Cf. Lev 18:7-20. St. Paul stigmatizes this especially grave offense: "It is actually reported that there is immorality among you . . . for a man is living with his father's wife.... In the name of the Lord Jesus ... you are to deliver this man to Satan for the destruction of the flesh...."¹⁸¹ 1 Cor 5:1, 4-5. Incest corrupts family relationships and marks a regression toward animality.