Marriage. Phratries and lineages are exogamous but have no preferred pattern of spouse exchange. Bilateral cross-cousin marriage is preferred and occurs among actual genealogical first cross cousins in approximately 18 percent of Recorded marriages. Polygyny is permitted, but it is infrequent because of the high cost of bride-price. Widow remarriage is not stigmatized. The junior levirate is encouraged, but widows are just as likely to marry a man from another family. Koyas have considerable freedom of choice in mate selection and pay only a token compensation to the mother's brother in the event that they do not marry a cross cousin. Most first Marriages are postadolescent. Postmarital residence is preferentially patrilocal, but bride-service is common and families without male heirs will often adopt a resident son-in-law. Divorce and remarriage are relatively easy and fairly frequent. The defecting spouse must pay compensation to the deserted spouse's family and pay a fine to the village council if it adjudicates the divorce.
Domestic Unit. The extended family is the main unit of cooperation, reproduction, and socialization. Many compromise family units arise from contingencies of the life cycle. Extended families split up after the death of the father or soon after the marriage of the youngest son.
Inheritance. The estate is subdivided equally among the male heirs and a portion is set aside for the dowry and Marriage expenses of any unmarried female children. One of the brothers continues to live in the family home with the surviving mother and her unmarried children. Other married male children construct new dwellings within the compound or in a new nearby location.
Socialization. Authority within the family is determined by gender, age, and competence. The eldest male, as long as he remains competent, has authority over all the others in most family matters, but his wife or widowed mother supervise all work done by females and younger children. When the father dies or becomes incompetent, the eldest son assumes authority unless he is immature, in which case the father's eldest surviving brother will take control until the son is old enough. Children are seldom directly instructed in proper behavior or in how to perform tasks. They learn by direct observation and imitation. What little instruction they get comes almost Entirely from older siblings and grandparents. Discipline for infractions is swift and certain and, in that coming from older siblings, often physical.