Animal Family

A "conjugal" family includes only the husband, the wife, and unmarried children who are not of age. The most common form of this family is regularly referred to in sociology as a nuclear family. A "consanguineal" family consists of a parent and his or her children, and other people. Although the concept of consanguinity originally referred to relations by "blood," cultural anthropologists have argued that one must understand the idea of "blood" metaphorically and that many societies understand family through other concepts rather than through genetic distance. A "matrilocal" family consists of a mother and her children. Generally, these children are her biological offspring, although adoption of children is a practice in nearly every society. This kind of family is common where women have the resources to rear their children by themselves, or where men are more mobile than women.
History of the family
The diverse data coming from ethnography, history, law and social statistics, establish that the human family is an institution and not a biological fact founded on the natural relationship of consanguinity.