Demographic and social aspects of twentieth-century low fertility populations: Three approaches

Katherine Alison Miller, University of Pennsylvania


The three chapters of this dissertation are freestanding papers, related only by their focus on developed, low-fertility populations. Chapter 1: Fertility often varies with period conditions, and some research has shown that the fertility of young women aged 20–24 responds most strongly to changing economic or social circumstances. This reanalysis of fertility rates among white women in the United States from 1920 to 1998 shows that heightened responsiveness to period factors can occur at any stage in the reproductive years, depending on parity, the nature of the period conditions, the time span included, and whether variability is measured on an absolute or relative scale. Cohort effects are treated as the age-period interaction, which provides for a natural interpretation and avoids underidentified regression models. Chapter 2: Assisted Reproductive Technology (ART) such as in-vitro fertilization was introduced in the United States in the 1980's. Through 1995 it became increasingly publicized, accessible, effective, ethically acceptable, and covered under health insurance plans. Did this advent in reproductive technology change the reproductive intentions of subfecund people? This analysis of three rounds of the National Survey of Family Growth finds that between 1982 and 1995, intentions to have a birth rose faster among subfecund women than among fecund women, standardized for age, parity, and education. Two competing hypotheses that could explain this trend are examined and dismissed. The development of ART may well have changed the reproductive intentions of subfecund women in the United States. Chapter 3: This paper examines stable population models using 1995 United Nations age structures and vital rates, with emphasis on the ageing, low-fertility, low-mortality populations of the late 20th century. As compared to previous high-fertility populations, these modern below-replacement populations have disorderly age structures and peaked net maternity functions (NMFs). These peaked NMFs result in extremely long times to reach stable form, as well as distinct oscillations in future old-age dependency ratios. These and other conclusions about the population dynamics of current below-replacement populations are explored.

Subject Area

Demographics|Families & family life|Personal relationships|Sociology

Recommended Citation

Miller, Katherine Alison, "Demographic and social aspects of twentieth-century low fertility populations: Three approaches" (2002). Dissertations available from ProQuest. AAI3054981.