FAMILY CODE SECTION 7650
7650. (a) Any interested person may bring an action to determine
the existence or nonexistence of a mother and child relationship.
Insofar as practicable, the provisions of this part applicable to the
father and child relationship apply.
(b) A woman is presumed to be the natural mother of a child if the
child is in utero after the death of the decedent and the conditions
set forth in Section 249.5 of the Probate Code are satisfied.