Under California law, a man 'is presumed to be the natural father of a child' in various circumstances involving his marriage or attempted marriage to the child's mother, or if he 'receives the child into his home and openly holds out the child as his natural child.' (Fam. Code, § 7611, subd. (d).) Section 7650 expressly directs that '[i]nsofar as practicable,' the provisions pertaining to the father and child relationship apply in determining the existence of a mother and child relationship. (§ 7650.)
In Nicholas H., 28 Cal.4th 56, the court held that a nonbiological father who receives a child into his home and holds the child out as his natural child can be the 'presumed' father of the child. If a nonbiological father can by his conduct meet the statutory definition of a presumed father, then by parity of reasoning a nonbiological mother can become a presumed mother. The legal presumption of fatherhood or motherhood created by receiving and holding out the child as one's natural child 'may be rebutted in an appropriate action only by clear and convincing evidence.' (§ 7612, subd. (a).)
It has long been a staple of the common law ...