In a groundbreaking study conducted by researchers from Pompeu Fabra University and their international collaborators, new insights have emerged into the profound influence of romantic relationships on fertility desires within Japan’s uniquely challenging demographic landscape. This research delves deep into the link between partnership status and how it shapes individual aspirations toward parenthood, highlighting critical psychosocial dynamics that could aid in understanding Japan’s persistently low fertility rates.
Japan stands as one of the world’s most pronounced examples of demographic decline, characterized by a notably high percentage of childless individuals and a strong cultural norm that nearly all childbearing occurs within the confines of marriage. Intriguingly, close to 70% of unmarried Japanese adults report not being involved in any romantic relationship, a factor that appears to be intricately connected to their expressed desires about having children. This societal backdrop presents a compelling case to explore the nuanced relationship between partnership status and fertility inclinations.
Using a robust dataset from the longitudinal Japanese Life Course Panel Survey (JLPS) spanning 2009 through 2023, the researchers focused on a sample demographic of men and women aged 20 to 49 years who had never had children. The longitudinal design enabled a detailed temporal tracking of the same individuals, rendering a high-resolution view of how relationship dynamics influence fertility preferences over time. The relationship status was meticulously categorized into four distinct groups: married, cohabiting, in a relationship but not cohabiting, and not in a relationship.
Fertility desires were also rigorously classified into three primary states: wanting children, being unsure, and not wanting children. By employing a fixed-effects analytical model—which controls for individual-specific unchanging characteristics—the study was able to isolate the impact of changes in relationship status on shifts in fertility desires, ensuring the observed effects were not confounded by stable personal factors but truly driven by partnership dynamics.
The findings were striking and revealed a pronounced tendency for childless individuals without a romantic partner to lower their fertility desires, most notably by shifting from a definitive “want children” stance to an “unsure” or even “do not want children” category. This trend was most acute in the transition from “wanting children” to “unsure,” underscoring a growing uncertainty rather than an outright abandonment of the desire to become parents. Importantly, this changing outlook often manifested promptly after individuals entered a non-partnered phase, suggesting that the absence of a partner has an immediate psychological and aspirational impact rather than a gradual erosion of fertility desires over time.
Even among those who remained single over extended periods, a significant minority—28% of women and 21% of men—maintained a consistent desire to have children, demonstrating that the absence of a partner does not necessarily equate to a diminished wish for parenthood. Conversely, a smaller segment consistently expressed no interest in children, highlighting substantial heterogeneity within the unpartnered population that is often overlooked in demographic and policy discussions.
This research sheds light on the critical psychological intermediary role romantic relationships play in shaping fertility desires. The presence of a partner appears to provide a context or a mental framework that consolidates and clarifies fertility intentions, whereas not having a partner injects uncertainty and modulates these desires, complicating individuals’ planning and expectations for parenthood.
From a policy perspective, the study suggests that treating unmarried individuals as a monolithic category is insufficient and potentially misleading. Instead, distinctions must be drawn between those actively involved in relationships and those who are not, as their fertility motivations and challenges markedly differ. Understanding the barriers single individuals face—not only structurally but also socially and psychologically—can illuminate targeted strategies to support those aspiring to parenthood.
Such insights call for a reevaluation of existing social and family policies that often overlook the complex realities surrounding dating, partnership formation, and the social integration of single adults. Economic instability, rigid work-life balance demands, and limited social interaction opportunities may all interplay to sustain the unmarried and unpartnered status of individuals with strong fertility desires. Hence, tackling these social barriers head-on may prove pivotal in enabling more people to realize their parenting goals.
The use of longitudinal data and sophisticated statistical modeling distinguishes this research, moving beyond cross-sectional snapshots to capture the fluidity and dynamics of life-course events. By tracking the same individuals over more than a decade, this approach offers an unprecedented lens to observe how partnership transitions can lead to immediate shifts in fertility preferences, thereby refining theoretical models of fertility decision-making.
Moreover, the emphasis on “uncertainty” as a distinct and measurable fertility desire category is innovative, recognizing that fertility intentions are often not binary or static but involve fluctuating ambivalence. This conceptual nuance is vital for demographic policymakers, social scientists, and reproductive health professionals aiming to understand and address low fertility rates in socio-cultural contexts like Japan’s.
The implications of this research are far-reaching, touching upon demographic sustainability, gender relations, reproductive health, and social policy design. By disentangling the role of romantic relationships from mere marital status and elucidating their immediate psychological effects on fertility desires, the study contributes to an enriched narrative about population dynamics in aging societies.
Future research directions highlighted by the authors include a more granular analysis of dating behaviors and the socioeconomic factors underpinning the persistent high rates of non-partnership among the never-parent population. A multidimensional understanding of how economic insecurity, workplace inflexibility, urban living conditions, and social networks influence both partnership formation and fertility desires is essential for comprehensive policy interventions.
To conclude, this pioneering study exposes how the fabric of romantic relationships critically weaves into the tapestry of fertility desires in Japan. It underscores a compelling truth—desire for children often remains alive even amid the absence of partners, yet this absence injects uncertainty and dampens fertility ambitions, potentially contributing to involuntary childlessness. Policymakers and social institutions must integrate these insights to craft nuanced, empathetic, and effective responses tailored to the diverse experiences of single adults and couples alike.
Subject of Research: People
Article Title: Exposure to non-partnership and fertility desires among childless population in Japan
News Publication Date: 5-Aug-2025
Web References: http://dx.doi.org/10.1093/sf/soaf123
References: Mogi, R., Mugiyama, R., Raybould, A. (August 2025). “Exposure to non-partnership and fertility desires among childless population in Japan.” Social Forces.
Keywords: Demography, fertility desires, romantic relationships, Japan, childlessness, longitudinal survey, fixed-effects model, social policy
