An Estimate of Male Subfecundity in the Gwembe Tonga of Zambia

Abstract

Primary and secondary sterility have been demonstrated to be elevated in sub-Saharan Africa in comparison to expectations for rates of sterility based on natural fertility populations. Despite being a condition of the couple, demographic measurement of sterility has previously only been done for women. With the availability of birth histories for Gwembe Tonga men from 1956-1996 from the Gwembe Tonga Research Project, this thesis uses the Larsen-Menken subsequently infertile measure and discrete time event history analysis to estimate male secondary sterility in this population. Secondary sterility is also estimated for the female population of the Gwembe Tonga as well as from four Zambia Demographic and Health Surveys (1992, 1996, 2001-02, and 2007) to explore differences between the sexes and trends over time. Male subfecundity is found to be similar to female subfecundity through the mid-thirties, after which women's sterility rates are much higher. Secondary sterility was also found to increase over time in the Zambia.