Two-Tier Fertility Decline in Nigeria: The Growing Discrepancy between Muslims and Christians

Marcin Stonawski, International Institute for Applied Systems Analysis (IIASA) and Cracow University of Economics
Michaela Potancokova, Wittgenstein Centre (IIASA, VID/ÖAW, WU)
Matthew Cantele, International Institute for Applied Systems Analysis (IIASA)
Vegard Skirbekk, International Institute for Applied Systems Analysis (IIASA)

At nearly 170 million, Nigeria is Africa’s most populous country by twofold and fertility levels remain higher than most other sub-Saharan African nations. Throughout the last several decades, the fertility gap between Christians and Muslims has grown, causing demographers to question the proximate causes for observed divergent trajectories. Where DHS of 1990 revealed a non-significant difference of .3 children, this figure had increased to 2.3 children by 2008. As TFR of Christians decreased significantly from 6.1 to 4.7 children per woman between 1990 and 2008, the TFR of Muslims increased from 6.4 to 7.1 children per woman. The timing of this divergence coincides with the formal institutionalization of Sharia law in 1999. We examine the role of religion on education, contraception, and family behavior. Finally, we touch upon the implications for population growth and the religious composition of Nigeria in the coming decades.