Cal. Gov't Code § 12955.2

For purposes of this part, “familial status” means one or more individuals under 18 years of age who reside with a parent, another person with care and legal custody of that individual, a person who has been given care and custody of that individual by a state or local governmental agency that is responsible for the welfare of children, or the designee of that parent or other person with legal custody of any individual under 18 years of age by written consent of the parent or designated custodian. The protections afforded by this part against discrimination
on the basis of familial status also apply to any individual who is pregnant , who is in the process of securing legal custody of any individual under 18 years of age, or who is in the process of being given care and custody of any individual under 18 years of age by a state or local governmental agency responsible for the welfare of children.