The birth order of a child is tied to the number of children born to or adopted by the mother. If there is an adopted child in the family, the birth order is determined by the date of adoption, and not the age of the adopted child. If the adopted child is not a Singapore Citizen (SC), his or her birth order is determined by the date of adoption, or the date the child becomes a SC, whichever is later. Step-children, children who are not Singapore citizens, or children given up for adoption are not counted in the birth order.