URBANA, Ill., USA – Fertility rates in much of Sub-Saharan Africa remain high, despite declining child mortality and improved access to contraceptives and female education — factors that generally lead to smaller families and improved economic conditions in developing countries. A new study from the University of Illinois Urbana-Champaign looks at men’s and women’s desired fertility in rural Tanzania, gauging some of the factors that influence how many children they want.

“This conversation about fertility preferences is very important to the demographic transition of Sub-Saharan Africa. Families may adopt family planning practices in the short term, yet still plan to have more children in the long term, presenting a puzzle for researchers and policy makers,” said corresponding author Catalina Herrera Almanza, assistant professor in the Department of Agricultural and Consumer Economics, part of the College of Agricultural, Consumer and Environmental Sciences at Illinois.

She co-authored the study with Aine Seitz McCarthy, associate professor of economics at Lewis & Clark College.

“There is evidence that people in poor, rural areas are having large families because they want to, not because they don’t have enough access to contraception. For households that depend on agricultural labor, wanting more children can make economic sense,” McCarthy said. “Men typically want more children than women, but we found that the husband’s preferences can strongly influence their wife’s.”

The researchers evaluated the results of a 15-month family planning program for rural households in Tanzania’s Meatu district, conducted in partnership with the country’s Ministry of Health and the Meatu District Hospital. Local women were trained to provide education on birth spacing, the safety of contraceptives, and free birth control options available from public dispensaries.

The study followed 515 households in 12 villages, randomly assigned to one of three groups: joint consultations for couples, individual consultations for wives only, and a control group. Before and after the program, each spouse was asked privately and separately by a person of their own gender how many additional children they wanted.

Participants were, on average, 37 years old for men and 30 for women, and already had five children. Before the intervention, 89% of women were not using contraception.

“The program triggered the opportunity for these men and women to learn about their spouse’s fertility preferences. Most of them had never talked about it before — about two-thirds of couples had never discussed how many children they wanted,” Herrera Almanza said.

The researchers found that men, on average, wanted 4 more children, while women would like 2.4. However, after participating in the couples consultations, both spouses’ fertility preferences increased. After the joint counseling, husbands desired an additional 0.77 children, while there were no differences for men who did not receive counseling.

Women who participated in joint counseling increased their desired fertility by 1.6 children. In contrast, women in the individual group reported lower desired fertility after the program. Furthermore, women in the couples’ group overestimated their husbands’ desire for more children after the consultations, while this was not the case for the individual group.

The researchers found the results were driven by women in polygamous marriages, which was nearly a third of the sample.

“In polygamy, this can be strategic behavior where women want children because there is no old-age security, and land inheritance follows the sons. A wife with more children might be able to claim more resources,” Herrera Almanza said.

Older women were also more likely to increase their fertility preferences, perhaps reflecting a strategic desire to have as many children as possible while they can.

The researchers speculated that power imbalances in the relationship might influence the result, causing women to say they want more children simply to appease their husbands.

“This increase in desired additional fertility might seem to be ‘cheap talk’ that may not be backed up by actual desire to increase your fertility. For example, women who are in a domestic violence situation may be fearful and therefore be willing to go along with what their husbands are saying. However, we didn’t find any evidence of that being the case. If anything, women who are more empowered in their household were more likely to increase their fertility preferences,” Herrera Almanza said.

People were overall very responsive to learning about contraceptives, but they want to use them to space their children out, not to have fewer children.

This is aligned with the policy of Tanzania’s Ministry of Health in Tanzania, which recommends spacing children two years apart to improve the health of both babies and mothers.

Many countries in Africa have a large proportion of young people, and this leads to policy discussions about addressing the demographic dividend by delaying the first birth for young women and men, so they can be more productive. Teen pregnancy is high, which decreases the chances of completing high school, Herrera Almanza explained.

The study highlights the dichotomy between uptake in contraceptives and preference for large families.

“If the policy goal is to address the women's desired fertility and have healthier birth spacing, then it would make more sense to have joint family planning consultations, but to avoid asking couples about the number of children they want, and allow those discussions to happen more organically,” McCarthy said.

While this study only measured fertility preferences, the researchers are in the process of conducting follow-up interviews with participants, and preliminary results suggest that women are having the children they indicated they would.

The study, “Strategic responses to disparities in spousal desired fertility: experimental evidence from rural Tanzania”, is published in the Journal of Population Economics [DOI: 10.1007/s00148-025-01142-y].