California Code, Code of Civil Procedure - CCP § 1279.6

(a) Refuse to do business with a person, or refuse to provide the service to a person, regardless of the person's marital status, because he or she has chosen to use or regularly uses his or her birth name, former name, or name adopted upon solemnization of marriage or registration of domestic partnership.

(b) Impose, as a condition of doing business with a person, or as a condition of providing the service to a person, a requirement that the person, regardless of his or her marital status, use a name other than his or her birth name, former name, or name adopted upon solemnization of marriage or registration of domestic partnership, if the person has chosen to use or regularly uses that name.