The paper describes a research project to determine fertility-related family decision making processes. Fertility-related decisions are interpreted as all ultimate choices made by spouses concerning the number and spacing of children they will have. Specifically, the research investigated how factors such as the desire for more or less egalitarian role status between husband and wife, socio-economic influences, and individual needs and desires led spouses to arrive at a decision as to family size. The hypothesis is that choice of family size is influenced directly by social psychological processes within the household and indirectly by social and economic variables. Social psychological processes are based on attitudes, personalities, and interpersonal orientations of the husband and wife. A sample of 229 married couples was interviewed concerning desired and intended family size. Findings generally supported the hypothesis. The conclusion is that social exchange processes within the family are major determinants of family size and that these processes are influenced by social and economic variables. (DB)