Diverse data from ethnography, history, law, and social statistics, reveal the human family as a social institution and not as a biological fact founded on the relationship of consanguinity. The different types of families occur in a wide variety of settings, and their specific functions and meanings depend largely on their relationship to other social institutions. Although early western cultural anthropologists and sociologists considered family and kinship to be universally associated with relations by "blood" (based on ideas common in their own cultures) later research has shown that many societies instead understand family through ideas of living together, the sharing of food (e.g. milk kinship) and sharing care and nurture. Sociologists have a special interest in the function and status of family forms in stratified (especially capitalist) societies.