CA Fam Code Section 9306

(a)

Except as provided in subdivision (b), the birth parents of a person adopted pursuant to this part are, from the time of the adoption, relieved of all parental duties towards, and all responsibility for, the adopted person, and have no right over the adopted person.

(b)

Where an adult is adopted by the spouse of a birth parent, the parental rights and responsibilities of that birth parent are not affected by the adoption.