Government Code §573.023

(a) The degree of relationship by consanguinity between an individual and the individual's descendant is determined by the number of generations that separate them. A parent and child are related in the first degree, a grandparent and grandchild in the second degree, a great-grandparent and great-grandchild in the third degree and so on. (b) If an individual and the individual's relative are related by consanguinity, but neither is descended from the other, the degree of relationship is determined by adding: (1) the number of generations between the individual and the nearest common ancestor of the individual and the individual's relative; and (2) the number of generations between the relative and the nearest common ancestor. (c) An individual's relatives within the third degree by consanguinity are the individual's: (1) parent or child (relatives in the first degree); (2) brother, sister, grandparent, or grandchild (relatives in the second degree); and (3) great-grandparent, great-grandchild, aunt who is a sister of a parent of the individual, uncle who is a brother of a parent of the individual, nephew who is a child of a brother or sister of the individual, or niece who is a child of a brother or sister of the individual (relatives in the third degree).