Half blood is the relationship existing between persons having only one parent in common or relatives by blood but having only one common ancestor.
Statutes provide that kindred of the half blood inherit equally with those of the whole blood in the same degree, unless the inheritance came to the intestate by descent, devise, or gift of some one of his ancestors, in which case all those who are not of the blood of such ancestor must be excluded from such inheritance in favor of those who are. [Estate of Ryan, 21 Cal. 2d 498 (Cal. 1943)].