Abstract
Summary: Data were analysed from the 1973 surveys of the Nigerian segment of the Changing African Family (CAFN) Project which covered Yoruba women and men in Ibadan and the western state of Nigeria. The Yoruba women in monogamous unions and those in polygynous unions show slightly varying levels of fertility, measured as mean number of children ever born. Most of this variation can be attributed to other variables; type of union of the women does not significantly affect their fertility level.