California Code, Penal Code - PEN § 645

(a) Any person guilty of a first conviction of any offense specified in subdivision (c), where the victim has not attained 13 years of age, may, upon parole, undergo medroxyprogesterone acetate treatment or its chemical equivalent, in addition to any other punishment prescribed for that offense or any other provision of law, at the discretion of the court.

(b) Any person guilty of a second conviction of any offense specified in subdivision (c), where the victim has not attained 13 years of age, shall, upon parole, undergo medroxyprogesterone acetate treatment or its chemical equivalent, in addition to any other punishment prescribed for that offense or any other provision of law.

(c) This section shall apply to the following offenses:

(d) The parolee shall begin medroxyprogesterone acetate treatment one week prior to his or her release from confinement in the state prison or other institution and shall continue treatments until the Department of Corrections demonstrates to the Board of Prison Terms that this treatment is no longer necessary.

(e) If a person voluntarily undergoes a permanent, surgical alternative to hormonal chemical treatment for sex offenders, he or she shall not be subject to this section.

(f) The Department of Corrections shall administer this section and implement the protocols required by this section. Nothing in the protocols shall require an employee of the Department of Corrections who is a physician and surgeon licensed pursuant to Chapter 5 (commencing with Section 2000) of Division 2 of the Business and Professions Code or the Osteopathic Initiative Act to participate against his or her will in the administration of the provisions of this section. These protocols shall include, but not be limited to, a requirement to inform the person about the effect of hormonal chemical treatment and any side effects that may result from it. A person subject to this section shall acknowledge the receipt of this information.