CALIFORNIA FAMILY CODE
CHILD OF WIFE COHABITING WITH HUSBAND
PRESUMED CHILD OF MARRIAGE
Family Code Section 7540
(a) Except as provided in Section 7541, the child of spouses who cohabited at the time of conception and birth is conclusively presumed to be a child of the marriage.
(b) The conclusive marital presumption in subdivision (a) does not apply if the court determines that the husband of the woman who gave birth was impotent or sterile at the time of conception and that the child was not conceived through assisted reproduction.