Hindu Adoptions and Maintenance Act, 1956
14. Determination of adoptive mother in certain cases
(1) Where a Hindu who has a wife living adopts a child, she shall be deemed to be the adoptive mother.
(2) Where an adoption has been made with the consent of more than one wife, the senior-most in marriage among them shall be deemed to be the adoptive mother and the others to be step-mothers.
(3) Where a widower or a bachelor adopts a child, any wife whom he subsequently marries shall be deemed to be the step-mother of the adopted child.
(4) Where a widow or an unmarried woman adopts a child, any husband whom she marries subsequently shall be deemed to be the step-father of the adopted child.