Fertility levels in global regions and countries: what is the role of religion?

Population growth depends strongly on fertility rates, so it is important to study factors that determine fertility. Despite much research, there is no consensus about the most important factors involved, except that contraceptive use can be effective. Factors correlated with declining as well as increasing or high fertility should be studied simultaneously. Religiosity is potentially important, but it has been difficult to quantify. Studies suggest it has increased globally over the past 30 years. A new TOP study of six global regions finds positive correlation between degree of religiosity and fertility. Educating women and other factors may counteract religiosity and produce continued fertility decline, but whether they will they do so in the long term is uncertain.

By Frank Götmark and Malte Andersson

TOP now announces a new highly relevant publication: Human fertility in relation to education, economy, religion, contraception, and family planning programs. In this new study in BMC Public Health (1) we use country data to investigate how total fertility rate (TFR, number of children born per woman) is related to education (school years for women), economy (GDP per capita), religiosity, use of modern contraceptives, and family planning program strength. We use global regions to provide a broad new picture of associations between fertility and these five factors.

We sorted 141 countries into six regions based on geography and their degree of other associations (economy, culture, history), as follows; Western Europe and associated countries (also overseas, e.g. USA), Eastern Europe, Latin America and the Caribbean, the Arab States, Sub-Saharan Africa, and Asia. Most data come from UN-related sources; religiosity data are from Gallup surveys. A published index was used for family planning program strength.

For the six regions we find a clear negative correlation between school years for women and average fertility rates (TFR). Thus, there is an association between number of school years and lower TFR. Economy (GDP per capita – flow of capital) and contraceptive use also have negative correlation with TFR, contraceptive use showing the strongest correlation. We analysed family planning program strength in four regions and found negative associations with TFR, though not in Sub-Saharan Africa. Religiosity on the other hand is positively correlated with TFR among the six global regions. Sub-Saharan Africa and the Arab States have the highest TFRs and also the highest degree of religiosity, whereas the European regions have the lowest values. Graphs below show TFR versus education of women, and TFR versus religiosity.

What we know about the factors pic

Fertility is clearly lowest in Eastern and Western Europe, with TFR below the replacement level of 2,1. Asia and Latin America are intermediate with respect to TFR, and also similar. In Arab States TFR is higher and Sub-Saharan Africa stands out, with very high TFR.

Exploring TFR in each region separately (using countries as units) we discovered some unexpected results. TFR decreases with increased number of school years in Arab States and Sub-Saharan Africa, but it increases with school years in Western Europe. TFR increases with religiosity in Asia and Sub-Saharan Africa, but is unrelated to religiosity in Eastern and Western Europe. This pattern in Europe may be different for religiosity within a country, as shown in some studies. TFR decreases most strongly with use of contraceptives in Latin America, Asia and Sub-Saharan Africa, but the level of use has no clear effect in Eastern Europe, where traditional contraception (withdrawal, safe periods) and abortion are more common. (See Figures and more information in the study).

We also used countries as units to examine how four factors themselves (school years, GDP per capita, religiosity, contraception) were related pairwise to each other, within each global region. This can help clarify their broader influence in a society, and their combined influence on TFR. A consistent pattern in all regions emerged: school years, GDP per capita, and contraception were positively related to each other, but religion was negatively related to these three factors (Figure 6 in the study, see also reference 2 below).

The resistance of the Vatican and several Muslim countries to modern contraceptives and abortion is well known, documented e.g. at the UN conference on population and development in 1994 (3). Yet few Catholic countries have followed the Popes’ declarations (4). For instance, in mainly Catholic Latin America, modern contraceptives are largely acceptable and commonly used in many countries, and TFR levels are not very high.

The Arab States and particularly Sub-Saharan Africa have high TFR, and also slower declines in fertility over time compared to other global regions. The UN forecasts almost a threefold population increase in Sub-Saharan Africa by 2100, which is alarming (but rather neglected by the UN). Patriarchal structure and high ideal family size contribute to the present high TFR (5), but as suggested by our study, religiosity may also be an important factor counteracting declining fertility in Sub-Saharan Africa.

Many highly educated persons in Western nations, including researchers in ecology, sustainability and demography, seem to be unaware of, or neglect, the global rise of religiosity. But increasing religious belief, either in Christianity, Islam, or other forms of faith in the supernatural, have been documented in recent years (e.g. 6-12). One can object that no automatic link exists between high degree of religiosity and high TFR; indeed, Iran and Tunisia provide examples of effective family planning programs in countries with high religiosity. There are also many examples of individual Catholic priests who have supported the use of modern contraceptives. But even so, our results suggest that high TFR is associated with religiosity in several global regions. Moreover, several family planning programs are historical examples and unfortunately ended (for instance, in Iran and Turkey).

It seems clear that the future large increase in human population will be outside the Western world, in Asia, the Arab States, and particularly in Sub-Saharan Africa. The proportion of religious people will almost certainly continue to rise, in large part because of higher birth rates among the religious, and the secular proportion will continue to drop. In Africa, a large part of international development aid is distributed by so called faith-based NGOs, helping to build school and health systems (e.g. 13). How much information is given in these educational and health contexts about desirable family size and modern contraceptives? In Sub-Saharan Africa, the average contraceptive prevalence rate is only about 25%, and much lower in many of the countries.

Conclusions about the main factors that determine fertility and population levels vary among researchers. Some conclude that food availability is crucial, for us as for other animals (14), others emphasize the number of school years for women (15), still others point to family planning programs (16). What is the role of religiosity today—and what will it be in the future?

TOP is planning more studies to answer this and other important questions related to population growth and fertility.


Please Note: The Overpopulation Project (TOP) presently needs donations to be able to continue its work, from June and onwards. We hope to employ two new assisting researchers for another two-year period, if we obtain funding. If so, we can continue our active research and outreach, including the website. We reach many readers especially in the US, UK, Sweden and India, and in addition have readers in 187 other countries, according to WordPress. For more information about possible donations and about our work, please contact Dr Frank Götmark, frank.gotmark@gu.se.



  1. Götmark, F & Andersson, M. Human fertility in relation to education, economy, religion, contraception, and family planning programs. BMC Public Health 20:265; 2020.https://doi.org/10.1186/s12889-020-8331-7
  2. de la Croix, D & Delavallade, C. Religions, fertility, and growth in South-East Asia. Int Econ Rev (Philadelphia) 59: 907–46; 2018. https://doi.org/10.1111/iere.12291.
  3. Johnson, S. The politics of population: Cairo. London: Earthscan; 1995.
  4. Calderisi, R. Earthy mission. The Catholic church and world development. New Haven: Yale University Press; 2013.
  5. Korotayev, A. et al. Explaining current fertility dynamics in tropical Africa from an anthropological perspective. Cross-Cultural Res. 50: 251–80; 2016. https://doi.org/10.1177/1069397116644158.
  6. Kaufmann, E. Shall the religious inherit the Earth? Demography and politics in the twenty-first century. Profile Books; 2010.
  7. Johnson TM, Grim BJ. The world’s religions in figures. Chichester: Wiley-Blackwell; 2013.
  8. Adogame, A. & Shankar, S. Religion on the move! New dynamics of religious expansion in a globalizing world. Brill; 2013.
  9. Stark R. The triumph of faith. Wilmington: ISI Books; 2015.
  10. Hackett, C. et al. The future size of religiously affiliated and unaffiliated populations. Demogr. Res. 32: 829–42; 2015. https://doi.org/10.4054/DemRes.2015.32.27.
  11. Stonawski, M. et al. The changing religious composition of Nigeria: causes and implications of demographic divergence. J. Mod. Afr. Stud. 54: 361–87; 2016. https://doi.org/10.1017/S0022278X16000409.
  12. Ross, K.R. et al. Christianity in Sub-Saharan Africa. Edinburgh University Press; 2017.
  13. Leblanc, N.M. & Gosselin, L.A. (Editors) Faith and charity. Religion and humanitarian assistance in West Africa. Pluto Press; 2016.
  14. Warren, S.G. Can human populations be stabilized? Earth’s Futur. 3: 82–94; 2015. https://doi.org/10.1002/2014EF000275.
  15. KC, S & Lutz, W. The human core of the shared socioeconomic pathways: population scenarios by age, sex and level of education for all countries to 2100. Glob. Environ. Change 42: 181–92; 2017. https://doi.org/10.1016/j.gloenvcha.2014.06.004.
  16. De Silva, T. & Tenreyro, S. Population control policies and fertility convergence. J. Econ. Perspect. 31: 205–28; 2017. https://doi.org/10.1257/jep.31.4.205.

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