California Code, Probate Code - PROB § 1207

(a) Subject to subdivision (b), where notice is required to be given to a decedent's beneficiaries, devisees, or heirs, notice need not be given to a person who, because of a possible parent-child relationship between a stepchild and a stepparent or between a foster child and a foster parent, may be (1) an heir of the decedent or (2) a member of a class to which a devise is made.

(b) Subdivision (a) does not apply where the person required to give the notice has actual knowledge of facts that a person would reasonably believe give rise under Section 6454 to the parent-child relationship between the stepchild and the stepparent or between the foster child and the foster parent.