California Code, Health and Safety Code - HSC § 102705

All records and information specified in this article, other than the newly issued birth certificate, shall be available only upon the order of the superior court of the county of residence of the adopted child or the superior court of the county granting the order of adoption.

No such order shall be granted by the superior court unless a verified petition setting forth facts showing the necessity of the order has been presented to the court and good and compelling cause is shown for the granting of the order. The clerk of the superior court shall send a copy of the petition to the State Department of Social Services and the department shall send a copy of all records and information it has concerning the adopted person with the name and address of the natural parents removed to the court. The court must review these records before making an order and the order should so state. If the petition is by or on behalf of an adopted child who has attained majority, these facts shall be given great weight, but the granting of any petition is solely within the sound discretion of the court.

The name and address of the natural parents shall be given to the petitioner only if he or she can demonstrate that the name and address, or either of them, are necessary to assist him or her in establishing a legal right.