North Carolina General Statutes Chapter 51. Marriage § 51-4. Prohibited degrees of kinship

When the degree of kinship is estimated with a view to ascertain the right of kinspeople to marry, the half-blood shall be counted as the whole-blood: Provided, that nothing herein contained shall be so construed as to invalidate any marriage heretofore contracted in case where by counting the half-blood as the whole-blood the persons contracting such marriage would be nearer of kin than first cousins; but in every such case the kinship shall be ascertained by counting relations of the half-blood as being only half so near kin as those of the same degree of the whole-blood.