Ferguson

This is an appeal from a summary judgment for defendant in a paternity action; the action was filed June 20, 1979, and judgment entered August 5, 1980. Derek is the minor who seeks to establish Thomas as his natural father. Derek’s mother is Shirley, and at the time of Derek’s conception and birth she was lawful ly married to Robert and cohabiting with him. The issue to be determined is whether Derek was entitled to obtain an HLA test of Thomas and to produce the result in evidence if it established paternity. The trial court had denied without prejudice motions to obtain such evidence, concluding that the presumption of Robert’s paternity made such evidence immaterial.

We affirm the judgment. As we have noted, judgment in this case was rendered August 5, 1980. The applicable law as of that date was contained in Evidence Code section 621, which read: “Notwithstanding any other provision of law, the issue of a wife cohabiting with her husband, who is not impotent or sterile, is conclusively presumed to be a child of the marriage.”

This legislative declaration is really not a presumption but a rule of substantive law. (Jackson v. Jackson (1967) 67 Cal.2d 245, 247 [ 60…