如果普遍了对整个社会次序都有影响
世界上大多数社会都是unilinear，而父系比母系要common 得多。dual descent非常少见因为很混乱，难道中国要退化成那样的原始社会。
Patrilineality (or agnatic kinship) is a system in which one belongs to one's father's lineage. It generally involves the inheritance of property, names or titles through the male line as well.
A patriline is literally a father line; one's patriline is one's father and his father and his father... ad infinitum, one's nearly infinite line of fathers. The two corresponding adjective forms are patrilineal and father-line. One's patriline is thus a line of descent from a male ancestor to a descendant (of either sex) in which the individuals in all intervening generations are fathers. A man's genetic Y-DNA and his family name (in most cultures) have descended down this same line from father to son. In a patrilineal descent system (= agnatic descent), an individual is considered to belong to the same descent group as his or her father. This patrilineal descent pattern is much more common than matrilineal descent, see the article on family names which are almost all patrilineal surnames. Also for an indepth treatment of current patrilineal surnames, globally, see the same article.
The agnatic ancestry of an individual is that person's pure male ancestry. An agnate is one's genetic relative exclusively through males: a kinsman with whom one has a common ancestor by descent in unbroken male line.
In cultural anthropology, a patrilineage (or patriclan) is a consanguineal male and female kin group each of whom is related to the common ancestor through male forebears.
Many societies construct kinship groupings, roles, and relationships by tracing descent exclusively through the male - patrilineal - or female - matrilineal - line. The resulting units are called unilineal descent groups, either patrilineages or matrilineages according to the prevailing descent rule. Unilineal kinship institutions occur at over twice the incidence of cognatic ones among the world's cultures. In many societies, unilineal descent groups assume important corporate functions such as land ownership, political representation and mutual aid and support.
Patrilineal societies are much more common than matrilineal ones, occurring at roughly twice the incidence and accounting for 60% of all unilineal systems and 40% descent systems (unilineal and cognatic) thoughout the world. They may be familiar to you from the Bible, (the "tribes" of Israel were patrilineages) and ancient Greek and Roman family organization. Matrilineal systems are less frequent but are still ethnographically important. The powerful West African Ashanti kingdom developed within a matrilineal society. Accordingly, the heir to the throne is not the king's (Asantehene's) own child but his sister's son. Early British emissaries to Ashanti learned about this family system the hard way. They supported several of the Asantehene's sons to be educated in England only to realize that the allies they had so carefully cultivated were not in line to assume the throne.
A third unilineal form, dual descent, involves the presence of significant patrilineal and matrilineal groupings in single society. Their occurance is relatively rare.
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