Patrilines, patrilocality and fertility decline in Viet Nam

The 90 per cent or so of the Vietnamese population who belong to the Kinh ethnic group (Vietnam, 1991: volume 1, table 1.4) have a patrilineal, patrilocal family system. To conform to the rules of this system, a couple must have at least one biological or adopted son, Viet Nam’s dramatic fertility decline has, however, entailed a rise in the proportion of parents unable to fulfil this condition. What does this imply about the strength of Viet Nam’s patrilineal, patrilocal norms, now and in the future?