S.C. Code Ann. § 20-1-10: Persons who may contract matrimony.

(A) All persons, except mentally incompetent persons and persons whose marriage is prohibited by this section, may lawfully contract matrimony.

(B) No man shall marry his mother, grandmother, daughter, granddaughter, stepmother, sister, grandfather's wife, son's wife, grandson's wife, wife's mother, wife's grandmother, wife's daughter, wife's granddaughter, brother's daughter, sister's daughter, father's sister, mother's sister, or another man.

(C) No woman shall marry her father, grandfather, son, grandson, stepfather, brother, grandmother's husband, daughter's husband, granddaughter's husband, husband's father, husband's grandfather, husband's son, husband's grandson, brother's son, sister's son, father's brother, mother's brother, or another woman.