Cal. HSC § 7113

A cemetery authority or licensed funeral director or a licensed hospital or its authorized personnel may permit or assist, and a physician may perform, an autopsy of any remains in its or his custody if the decedent, prior to his death, authorizes an autopsy in his will or other written instrument, or upon the receipt of a written authorization, telegram, or a verbal authorization obtained by telephone and recorded on tape or other recording device, from a person representing himself to be any of the following:

(a) The surviving spouse; (b) a surviving child or parent; (c) a surviving brother or sister; (d) any other kin or person who has acquired the right to control the disposition of the remains; (e) a public administrator; (f) a coroner or any other duly authorized public officer. A cemetery authority or a licensed funeral director or a licensed hospital or its authorized personnel is not liable for permitting or assisting, and a physician is not liable for performing, an autopsy pursuant to such authorization unless he or it has actual notice that such representation is untrue at the time the autopsy is performed. If such authorization is contained in a will, the autopsy may be performed regardless of the validity of the will in other respects or of the fact that the will may not be offered for or admitted to probate until a later date.

This section shall not authorize the obtaining of a verbal authorization by telephone and recorded on tape or other recording device for an autopsy of a deceased person if it is made known to the physician who is to perform the autopsy that the deceased was, at the time of his death, a member of a religion, church, or denomination which relies solely upon prayer for the healing of disease.