PIP: For centuries, illegitimate children, those born outside of civil marriage or a marriage conducted within the church, were systematically accorded second-class status by both the law and religion. This attitude toward such children frustrates efforts to change legislation, social structure, and our understanding of new types of union outside of marriage. In Canada, no common term even exists in the two official languages to designate the cohabitation of an unmarried couple. Such unions simply fall through the net of classical demography. Even the more dynamic approaches, such as those seen in multistate models, follow only the movements of individuals in traditional categories. One must understand that the formation of couples is a multidimensional process and that a multidimensional approach to such unions could lead to the creation of a new group of nonethnocentric categories applicable to a number of different societies. The authors also consider the notion of process, in which marriage and cohabitation are merely two states in a range of possible states through which an individual will move during the course of his or her life. Cohabiting situations vary in importance depending upon one¿s states. Better demographic analyses can lead to greater understanding of the human couple and its sexual and reproductive behaviors.