Bilineal descent is system of family descent where blood links and rights of inheritance through both male and female ancestors are of equal importance. Bilineal descent is system is tracing kinship structure through both parents. The most common form is bilateral descent. A system of tracing descent through both the mother’s and father’s sides of the family. A cloned child has unilineal descent, not bilineal descent; he or she is genetically kin to only one progenitor. Double or Duo lineal or Bilineal Descent is a form of unilineal descent which combines both patrilines and matrilines. Bilineal Descent is practiced by approximately 33% of cultures. Bilineal descent is primarily found in foraging and industrial societies where society is more egalitarian and gender-equal.
In most societies where kinship connections are important, the rules of descent affiliate individuals with different sets of kin. In India we generally find the patrilineal descent and matrilineal descent systems. The Daughters of the American Revolution is a bilineal descent category. The descendants of Abraham Lincoln may be defined as a bilineal descent category. The Toda of southern India also follow bilineal descent. Their property is inherited patrilineally and ritualistic privileges related to funerals are inherited matrilineally.
The Yoko of southeastern Nigeria are an example of a society with bilineal descent. Their important portable property, including livestock and money, are inherited matrilineally. Fixed property, such as farm plots, pass down through the patrilinal line as do rights to trees and other forest products. It is not surprising that they have patrilineally inherited obligations to cooperate in cultivating their fields. Obligations to perform funerals and pay bride price for sons are inherited through the matrilineal line.
In India we generally find the patrilineal descent and matrilineal descent systems. Of the two, patrilineal descent system is more common. Patrilineal descent is more prevalent in North India. Among the tribals, many tribes such as Santhals or Mundas have the patrilineal system. Interestingly the Todas who practice polyandry too have a patrilineal system.
The residency of Bilineal Descent cultures are usually neolocal residence - Which means the new offspring leave the nest to create a new home someplace else away from extended family. The most common household type for cultures practicing Bilineal Descent is nuclear or single-parent.