Human congenital relationship

Symbolic representations of cogenital and other kinship relationships are usually focused on the nuclear family of parents and children. Symbols include the relationship-defined identities of father, mother, child or siblings (brothers, sisters), and are extended to grandfathers, and grandmothers. A vertical relationship may be depicted by symbols of ancestors or forebears and by a representation of descendants. Diagonally and horizontally, kinship (clan) symbols may encompass fathers' and mothers' brothers and sisters, their spouses and their children, the spouses' parents and the childrens' spouses and the childrens' children. Special relationship symbols are those of twins (though rarely of other multiple human births), of order of birth, and order of spouse (e.g. second wife).

These symbols are very explicit and on the whole are self-referring. However, the symbol of a father may indicate paternity or authorship; that of a mother, origin; and that a child, development. Ancestors may represent lineage; descendants may indicate long-range implications and effects. Twins may indicate a quantitative doubling, or a qualitative duality or complementarity.