Marriage. Preferred and proscribed marriages are commonly recognized. Though parents prefer to arrange their children's marriages, especially educated young people would rather choose their own mates. Marriage is preferably with a person between the degree of first and fifth cousin. Distinctions are made between parallel and cross cousins; marriages between the former are avoided. Although most Iban marriages are monogamous, isolated instances of sororal and nonsororal polygyny occur. Marriage between a man and a woman who are related as members of adjacent generations is not approved, but propitiatory rites can be performed if, for example, an aunt and nephew insist on marrying. Marriage within the kin group is preferred to protect property rights and to avoid union with a descendant of slaves or a person of ill fortune. Residence is ambilocal or neolocal. Divorce may be initiated by either partner and, with mutual consent, is relatively easy.
Domestic Unit. The bilik-family is an autonomous unit, able to join with other units of a longhouse or to detach itself. Iban become members of a family through birth, adoption, marriage, or incorporation. The family is responsible for construction of its own unit, production of its own food, and management of its own affairs. In a sample of 1,051 families, 60 percent were comprised of parents and children, 40 percent included grandparents. The family is a kin-based, corporate group that holds in trust land, sacred rice, sacred charms, ritual formulas, taboos, and heirloom gongs and jars. Traditionally, one son or daughter remained in the bilik to ensure continuity over time. With urban migration and mail service making possible postal remittances, an increasing number of parents have no adult child residing in the bilik with them.
Inheritance . Male and female children share equally in rights to real and other property so long as they remain members of their natal bilik. Children who move out of the bilik at marriage or for any other reason receive a small portion of the family estate, and in theory relinquish all rights to family land. In fact, however, they retain the right to request land for farming at the annual meeting commencing the agricultural year.
Socialization. At birth an infant becomes the center of attention and the subject of numerous rituals. Weaning is casual and discipline relaxed. During the farming season, children are left in the care of older people. By age 5, children wash their own clothes and by 8, girls help with domestic chores. Traditionally adolescent males would undertake "the initiate's journey," a trip of several months or years, from which they were expected to return with trophies. Adolescent females demonstrate their maturity with diligence and in the weaving of ceremonial cloths, baskets, and mats.