The paper discusses the relationship between social structure and fertility behavior in man. Focusing upon human fertility within the context of varying social groups, the document reviews recent interdisciplinary population studies. Information and interpretations from biology, ethnology, anthropology, history, and sociology are presented in four chapters. Chapter I offers an historical analysis of the relationship of social structure to group size. Studies of animal groups indicate several common ways in which animals handle close contact, including aggression, submission, and moving to unoccupied territory. Serious overcrowding of animals results in various forms of social pathology, such as cannibalism, hyper-sexuality, and homosexuality. Chapter II describes and gives examples of fertility regulation in human groups. One hypothesis is that human groups do make attempts to control population for survival purposes. Another hypothesis is that they are more often inspired by concern for scarce objects which give status than for basic survival resources. Chapter III identifies variables affecting fertility, including factors affecting exposure to intercourse, gestation, and fetal and infant mortality. The final chapter discusses fertility in developing nations and examines implications for population policy formation. The conclusion is that policy makers must attempt to understand the many socioeconomic, environmental, and personal influences which affect fertility decisions. A list of references concludes the document. (Author/DB)