Study Suggests Local Dating Markets May Influence Pregnancy and Newborn Health
A growing body of research suggests that the balance of men and women in local dating markets does more than shape romance. A new study published in the Journal of Public Economics suggests it may also influence the health of mothers and their newborns by shaping marriage patterns, infection rates and pregnancy outcomes.
Researchers found that women living in areas with relatively more men of the same age and race were more likely to give birth within marriage and less likely to experience certain pregnancy-related health complications.
How the dating market was measured
Lead author Krzysztof Zaremba of ITAM Business School approached dating as an economic market governed by supply and demand. Instead of relying on current census data, he used the sex ratio at birth in each county as a starting point for measuring long-term partner availability.
Because biological sex at birth is essentially random and slightly favors boys, small variations in the share of male births accumulate over time. Zaremba showed that in many U.S. counties, the sex ratio observed at birth continues to predict the composition of the adult dating pool up to 35 years later.
That persistence allowed the researcher to treat early birth cohorts as a natural experiment. By focusing on counties with between 200 and 5,000 births per year, where random swings in sex ratios are more pronounced, he aimed to isolate the effect of partner availability from broader economic and social trends.
A pronounced imbalance for Black women
The study underscores a longstanding demographic divide between Black and White Americans. Nationally, there are about 89 Black men for every 100 Black women of childbearing age, compared with roughly 102 White men for every 100 White women.
This shortage of Black men is closely tied to disproportionately high incarceration rates and higher mortality among young Black men. These factors reduce the pool of potential partners, particularly for Black women, who tend to form relationships within their own racial group.
Zaremba set out to test whether this scarcity of partners helps explain persistent racial disparities in maternal and infant health. By linking birth outcomes to historical sex ratios, he estimated how much of the disparity could be attributed to the structure of the local dating market.
Marriage rates and family formation
The analysis of approximately 7 million U.S. births between 2011 and 2019 revealed that even a modest increase in the share of available men shifted family formation toward marriage. When the local dating market became more favorable to women, marital birth rates increased while non-marital births declined.
Specifically, a small increase in the proportion of men was associated with a 9.7 percent rise in marital births from a baseline of 47 per 1,000 women. Over the same range, non-marital birth rates fell by about 11.2 percent from a baseline of 34.4 per 1,000 women.
Women were also nearly three percentage points more likely to be married at the time they gave birth in counties with relatively more men. Births in which fathers were not officially identified declined by around 1.5 percentage points, pointing to more stable partnerships and greater formal recognition of paternity.
Health benefits for mothers and babies
The effects of the dating market extended beyond marital status. The study found measurable improvements in maternal health in communities with more available male partners. These benefits included lower rates of sexually transmitted infections and certain pregnancy-related complications.
The proportion of mothers diagnosed with chlamydia during pregnancy fell by about 13 percent compared with an average prevalence of 1.9 percent. Maternal hypertension, a major risk factor for pregnancy complications, declined by roughly 17 percent from a baseline of 2.2 percent.
Other health indicators, including diabetes and syphilis during pregnancy, also trended in a favorable direction, although not all reached conventional levels of statistical significance. Even so, the overall pattern pointed toward healthier pregnancies in dating markets where women had greater bargaining power.
These improvements extended to newborns. The likelihood that a baby received a low APGAR score—a rapid assessment of a newborn's physical condition immediately after birth—fell by about 8.3 percent relative to a baseline rate of 2.4 percent. Lower APGAR risk suggests fewer infants required urgent medical intervention after delivery.
Bargaining power and relationship dynamics
Zaremba interprets the findings through the lens of bargaining power within relationships. When women have more potential partners to choose from, their outside options improve, strengthening their position in romantic and household negotiations.
In this environment, women may be better able to negotiate safer sexual practices, secure more stable commitments or leave unsatisfactory relationships. Those shifts in bargaining power may translate into lower infection risk, better prenatal care and healthier birth outcomes.
The author emphasizes that the observed effects are modest in size but far from trivial. Simulations suggest that if Black and White women experienced the same local sex ratios, racial disparities in several maternal and infant outcomes would narrow by approximately 5 to 10 percent.
For example, he estimates that eliminating the shortage of Black men would reduce the racial gap in marriage among mothers by around 3.8 percent. The difference in chlamydia prevalence between Black and White mothers would shrink by roughly 6 percent under equal sex ratios.
Limits and unanswered questions
The research focuses on smaller and mid-sized counties, where people tend to be less mobile and local birth cohorts play a larger role in shaping adult dating markets. As a result, the findings may not fully apply to large metropolitan areas, where dating markets are broader and more fluid.
The study also assumes that most people choose partners within their own race, age group and county. If people routinely form relationships across longer distances or demographic groups, local sex ratios would likely exert less influence on relationship dynamics and health outcomes.
Zaremba is careful not to present the findings as a direct policy argument regarding incarceration or criminal justice. His analysis relies on naturally occurring variation in birth sex ratios over decades, rather than changes in law enforcement or prison populations.
He also stresses that the results should not be interpreted as personal dating advice. Instead, they illustrate how population-level demographic conditions can shape average health outcomes by influencing women's bargaining position in relationships.
Implications for public health research
The findings contribute to a broader discussion of the social determinants of health by suggesting that demographic structures can influence maternal and infant outcomes alongside healthcare access and economic conditions. Partner availability is rarely considered in discussions of maternal health disparities, yet the evidence suggests it may play a measurable role.
Future research could examine how women adapt to constrained dating markets, including changes in migration, partner selection, contraception and the timing of childbirth. Another important question is how men respond to shifts in dating market dynamics, including potential effects on mental health.
By linking relationship markets to birth outcomes, the study offers an unconventional perspective on health inequality. It suggests that reducing maternal and infant health disparities may require attention not only to healthcare systems, but also to the demographic and social environments that shape family formation.
The paper, titled “The Effect of Dating Markets on Maternal and Neonatal Health,” highlights a subtle but important connection: where and with whom people are able to form relationships may leave a lasting imprint on the health of the next generation.
Article prepared by Dr. Alex Morgan.
