Marriage. All Nyinba men who have brothers marry jointly in fraternal polyandry. Over time, these marriages may become monogamous, due to deaths of brothers and occasional divorce. Thus household histories show 70 percent of marriages to have been initially polyandrous, although only half the marriages in 1983 remained so. Postmarital residence is ordinarily virilocal. Only when a family lacks sons will a daughter marry uxorilocally. Most uxorilocal unions are monogamous, although sometimes a second sister joins the Marriage, in sororal polygyny. Men whose wives are childless are encouraged to marry second wives and men extremely unhappy in their polyandrous marriages are sometimes permitted second wives by their families. This creates marriages that are both polygynous and polyandrous (less than 5 percent of extant marriages in 1983). In all such cases, the preference is for sororal polygyny. Polyandry is highly idealized in expressing fraternal unity; it is seen as economically advantageous, and it also confers political advantages in the village. Frictions between brothers seem to be minimized by practices ensuring equal sexual access to the common wife and by the designation of paternity, which gives brothers equal opportunity to father children within the common marriage. Divorce of men is rare, as is the divorce of women who have borne children.
Domestic Unit. Households are large and multigenerational, including, on average, 7.7 members and 2.6 generations in 1983. The wealthier households tend to be larger and to include a relatively greater proportion of men than the poorer ones. Membership in households accrues only through marriage or by legitimate birth (due to polyandry and polygyny, the children may have different parents). Polyandry also has the effect of creating low dependency ratios. Household membership presumes cooperation in productive labor and a share in what the household produces, both of which vary with age and gender.
Inheritance. Property is inherited jointly by all sons of the previous property-holding generation. When daughters marry, they receive a dowry of household goods, agricultural tools, and occasionally a domestic animal or rights to a small plot of land for lifelong use. Traditionally, never-wed women had rights to lifelong maintenance; now Nepali law entitles them to lifelong use rights in half the share given a son. In the rare cases of partition among brothers, property is divided according to per stirpes (equally between the branches of a Family) reckoning, a custom that may be due to Hindu Nepali Influence. Any household produced in partition that fails to maintain itself passes to the partitioners' brothers or their successors.
Socialization. Boys and girls are raised differently, as are first and later-born sons. Girls, for example, begin productive work at an earlier age and are expected to help care for their younger siblings. First-born sons are encouraged to take a leadership role in the family, to prepare them for later Household headship, and are taught to treat their brothers fairly, which is particularly critical for polyandry.