Chapter 3 Models of marital status and childbearing The chapter presents an investigation on those microeconomic models of marital status and childbearing that contains implications for female labor supply. The chapter focuses its discussion primarily on the developed countries principally the United States but refers to developing country issues where these are applicable. The role of economic variables as determinants of demographic behavior is often far more vivid and persuasive in developing nations than it is in the United States or Western Europe. The chapter presents a review for the United States of trends in those demographic variables that are strongly associated with female labor supply: age at first marriage marital dissolution age at first birth the number of children born over the life cycle and the age pattern of fertility. Demographers have uncovered pronounced empirical regularities in these variables at least in aggregate data; in some instances the patterns are regular enough to be summarized in parsimonious model schedules. These schedules are reviewed in the chapter. The chapter discusses that economists have left such regularities largely unexploited; the prior information embedded in model schedules may yield efficiency gains in estimation especially where aggregate data are concerned. The chapter concludes with a review of the recent efforts to establish regularities in micro data.