When definitions based on form, rather than actual social relations or activities and functions, are used to estalish eligibility for policies supposed to support families, they can threaten the welfare of some families . Therefore biology and egal status are easily accepted as determinants of family. These defintion can separate needy people from those who give them care and support (e. g. visiting rights in hospitals) probelm to specify relationships determined by blood, marriage or residenxe and exclude social relationships. Family and kin are social creations and not products of biology (anthropologist) Biological ties do not establish the domestic groups that provide mutual support and nurturance. The group that lives together , cooperate to produce its subsistence and cares for children has not alway consist of people tied by blood or marraige. Therefore ---- social functions and not biological or residential relations might be the way to of children identify family.