This report summarizes the outcome of "The Study on the Relationship between Fertility Behaviour and Size, Structure and Functions of the Family of the Family," which is funded by the UN Fund for Population Activities, the International Development Research Centre, the Government of Japan, and the UN Economic and Social Commission for Asia and the Pacific (ESCAP). The chapters in this report synthesize and draw on the reports of meetings held by the ESCAP secretariat and country experts to conceptualize and formulate the project, to discuss the results of the pretest, and to discuss the 1st country reports. These cross-cultural country studies raise a number of issues which have profound policy implications. A high degree of interaction with those members of the family obligation who might constitute the "extended family" is not necessarily detrimental to family planning adoption. The level of active discouragement by family planning by family members is less than program might suppose. Discouragement of family planning or pronatalist interventions did not come from all persons or categories of persons identified in the interactions table. The reinforcement of fertility norms across the entire extended family did not occur even in the most pronatalist societies. A rather unexpected result was the strength of interaction with non-kin friends and neighbors. These data suggest that the maintenance of existing family structures and interactions with family, friends, and neighbors may favor both family planning and old age security policy.