The Family Is A Social Institution Family is a social institution and has different definitions depending on who defines it. Anthropologists say a culture's biological and marital kinship rules and patterns of reciprocal obligations define family. Structure-functionalists say the patterns of reciprocal obligations among people and between structures of people and the greater society define family. Institutionalists define family as a "traditional," biological, procreative and child-rearing structure and emphasize the biological relationship among family members. Interactionists, on the ot