Cal. Health & Safety Code § 103425

(a) A person may file a petition with the superior court in any county seeking a judgment recognizing the change of gender and sex identifier to female, male, or nonbinary.
(b) If requested, the judgment shall include an order that a new birth certificate be prepared for the person reflecting the change of gender and sex identifier and any change of name accomplished by an order of a court of this state, another state, the District of Columbia, any territory of the United States, or any foreign court.
(c) Subject to the requirements of Section 103430, if requested, the judgment shall include an order that a new marriage license and certificate or confidential marriage license and certificate be prepared for the person reflecting the change to the designation of the person as bride, groom, or having neither box checked on the marriage license and certificate or confidential marriage license and certificate and any change of name accomplished by an order of a court of this state, another state, the District of Columbia, any territory of the United States, or any foreign court.
(d) Subject to the requirements of Section 103430, if requested, the judgment shall include an order that a new birth certificate be prepared for the person’s child or children reflecting the change to the designation of the person as mother, father, or parent and any change of name of the petitioner accomplished by an order of a court of this state, another state, the District of Columbia, or any territory of the United States, or foreign court.
(e) A petition seeking a judgment recognizing the change of gender and sex identifier to female, male, or nonbinary may be made to a superior court within this state, even if the person whose gender and sex identifier is proposed to be changed does not reside within the State of California, if the person is seeking to change the designation to reflect their gender on at least one of the following documents:
1. (1) A birth certificate that was issued within this state to the person whose gender and sex identifier is proposed to be changed.
2. (2) A birth certificate that was issued within this state to the legal child of the person whose gender and sex identifier is proposed to be changed.
3. (3) A marriage license and certificate or confidential marriage license and certificate that was issued within this state to the person whose gender and sex identifier is proposed to be changed.