Sociologist George Peter Murdoch who defined the universal Family concept stated:
“The nuclear family is a universal human social grouping. Either as the sole prevailing form of the family or as the basic unit from which more complex forms compounded, it exists as a distinct and strongly functional group in every society”
The concept of the pre industrial extended family is somewhat of a misrepresentation – when you consider death rates of working class families. The extended family is referred to as vertical extensions; Aunts, uncles, cousins and siblings –grandparents, children, and grandchildren who all live together, are referred to horizontal extensions - the sexual relationships, and are monogamous within the extended and nuclear family. Polygamous relationships do exist within extended family, although this is predominately within specific cultures and religions. Examples being in the Moslem faith the act of polygamy are still practised; further more there are Christian sects such as the latter Day Saints who still practise polygamy, although such relationships are not legal within the European or American laws.
The extended family can also be viewed as that of an extension to the nuclear family thru the inclusion of elders, such as grandparents, as many loan parents are female and they may well life or near their mothers, creating a matriarchal family extended unit. Extended reconstructed family, is considered to be when two opposite sex, or same sex adults with