Family Code, Art. 38

The following marriages shall be void from the beginning for reasons of public policy: (1) Between collateral blood relatives whether legitimate or illegitimate, up to the fourth civil degree; (2) Between step-parents and step-children; (3) Between parents-in-law and children-in-law; (4) Between the adopting parent and the adopted child; (5) Between the surviving spouse of the adopting parent and the adopted child; (6) Between the surviving spouse of the adopted child and the adopter; (7) Between an adopted child and a legitimate child of the adopter; (8) Between adopted children of the same adopter; and (9) Between parties where one, with the intention to marry the other, killed that other person's spouse, or his or her own spouse. (82)