Max Planck Research Group Biosocial | Biology, Social Disparities, and Development

Head: Laurel Raffington
 

Polygenic-Environment Interplay in Germany
Epigenetic Indices Connect Childhood Exposures and Development with Adult Aging
Social and Ethical Considerations in Sociogenomics
Innovation, Impact, and Knowledge Gained

Families transmit their social status, education levels, and health advantages to their children, leading to disparities in important life outcomes that persist across generations. These disparities are the focus of policy efforts across many levels and facets of government, but our efforts to ameliorate inequality are hampered by how little is known about the mechanisms of intergenerational transmission. Studies on intergenerational transmission, such as those examining whether the home environment affects offspring educational outcomes, have long faced the challenge of potential confounding by genetic inheritance, as parents and offspring share both environmental and genetic similarities. Traditional debates of nature versus nurture have evolved into inquiries about how genetic and environmental influences combine to shape complex human traits. It is now known, in general terms, that both nature and nurture are involved in intergenerational transmission, but understanding specific mechanisms, and combatting the misuse of genetics requires novel data, measures, study design, and concepts.

The MPRG Biosocial examines how genetic influences and social inequality combine to shape life-course trajectories with downstream consequences for adult socioeconomic attainments and aging-related health. The group integrates recent genomic advances into social science designs to deepen our understanding of lifespan development and aging. By training algorithms on large discovery cohorts (thousands or millions of individuals) and applying them to smaller target samples, genomic innovations enable researchers to quantify and forecast complex behavioral and social outcomes. There are three core research lines:

1. Polygenic-Environment Interplay on Complex Traits in Germany
2. Epigenetic Indices Connect Childhood Exposures and Development with Adult Aging
3. Social and Ethical Considerations in Sociogenomics

The group was recently extended to continue its work for an additional two years (total duration 2022–2029). It receives funding from the Max Planck Society, a National Institutes of Health R01 grant, the EU Horizon Europe program, and the Jacobs Foundation.

Polygenic-Environment Interplay in Germany

Observational studies investigating the origins of individual differences, such as whether parental stimulation increases offspring performance on academic tasks, have long faced the challenge of potential confounding by genetic inheritance, since parents and offspring share both environmental and genetic similarity. Family studies, including twin, adoption, and extended family designs, offer a robust method for exploring gene–environment interplay. This is because genetic differences between siblings are randomly assigned during meiosis, allowing studies to use this natural randomization for causal inference akin to randomized controlled trials. However, the metrics derived from behavior genetic designs are population estimates and do not directly translate to individual-level genetic measures. Yet, the era of big data genomics has generated individual-level DNA-based genetic measures of complex traits, such as polygenic indices. Polygenic indices are summary measures of genetic variants previously found to be associated with, for example, educational attainment or traits related to self-regulation in millions of people.

Because polygenic indices have robust—albeit small and noisy—associations with complex traits when applied to much smaller target samples, they have become increasingly available in biobank research and have led to significant advancements in various scientific fields. Presumably for historic reasons, Germany is underrepresented in this scientific endeavor. Yet, Germany presents a unique opportunity to study gene–environment interactions due to its profound historical and social shifts over the past 100 years, including the division and reunification of the country that is often leveraged as a quasi-experimental design.

Figure 2 plots preliminary evidence involving 1,930 individuals from the German Socioeconomic Panel (SOEP) that the magnitude of polygenic associations with education did not differ between East and West Germany before reunification but increased in East Germany thereafter (Fraemke et al., 2025). The observed amplification of education-genetic associations aligns with theories suggesting heightened genetic influences on educational behaviors during periods of greater social opportunity. The desirability of stronger genetic effects on education depends on educational policy goals. Meritocratic systems might favor stronger education-genetic effects, but when integrated into social welfare frameworks, they may also aim to address inequalities in wealth and health that could arise from genetic causes of educational disparities.

However, interpreting these preliminary findings is complex because polygenic indices capture a mixture of genetic, environmental, and socially stratified environmental differences between individuals and families (Aikins et al., 2024). First, "direct" genetic effects occur mainly through internal processes involving cells within the body (e.g., hair texture). Second, transactional genetic effects stem from a person's genome but require environmental interaction, like mental health and cognitive skills. Third, caregivers' genes, even those not transmitted during reproduction, can influence child outcomes through correlated environmental processes. This phenomenon of "indirect" genetic effects may underlie other intra-familial dynamics, affecting relationships between siblings and romantic partners by influencing shared environments and social interactions. Put differently, genes become environments. Fourth, associations of polygenic indices with outcomes may result from confounding due to unaccounted population stratification and nonrandom mating. Notably, this signal mixture of genetic and environmental processes is relevant to both psychological and medical-oriented polygenic indices. A new approach integrates genomic measures into family-based sampling to study direct, transactional, and indirect gene–environment interplay, whilst effectively accounting for population stratification.

A major limitation into this research is that these types of data are currently not available in Germany. To overcome this challenge, Laurel Raffington and Ralph Hertwig are collaborating with the Socio-Economic Panel (SOEP) team at the DIW Berlin to build the first large-scale, intergenerational, genetic and epigenetic dataset in Germany. They have secured a Max Planck Strategic Innovation grant (2025–2028) to invite approximately 40,000 individuals to participate in a voluntary genomic add-on in the 2027 household SOEP wave. This data resource can then be used to address questions such as: (a) which specific parental behaviors affect the development of cognition and self-regulation in children, controlling for genetic transmission from parent to children, and, (b) does the effect of eliminating school tracking on educational attainment depend on genetic dispositions? Adding a within-family genetic design to quasi-experimental social science designs can create a unique framework where both environmental and genetic differences can be interpreted as exogenously assigned, thereby providing causal estimates.

Key References

Epigenetic Indices Connect Childhood Exposures and Development with Adult Aging

Epigenetic mechanisms, such as DNA methylation, regulate gene–environment interplay and sustain information over a lifetime, being both stable (e.g., encoding cell identity) and malleable (e.g., changing with age and behavioral interventions). Microarray chips measure whether a methyl group is attached to a genomic site at over 900,000 locations. Somewhat akin to polygenic indices, "epigenetic indices" apply algorithms to DNA methylation patterns to generate indices of biological age (i.e., "epigenetic clocks"), morphometric characteristics, or cognitive performance (i.e., "Epigenetic-g").

When applied to children, twin research has confirmed that these epigenetic indices reflect both genetic and environmental effects (Raffington, Schneper, et al., 2023). Moreover, epigenetic indices consistently correlate with childrens BMI, pubertal timing, cognition, and mental health (Aikins et al., 2024; Raffington et al., 2023). Collectively, these findings support the notion depicted in Figure 2 that epigenetic development and aging are to some degree connected and that epigenetic indices may be a promising tool for tracing the connection between childhood development with aging-related outcomes in adults (Raffington, 2024).

Additionally, three lines of evidence show that epigenetic indices of cognition and aging are sensitive to socioeconomic contexts. First, preregistered observational research across multiple cohorts is consistent with the theory that individuals in low socioeconomic status contexts have faster biological aging, worse cognitive performance, and higher adult BMI, as indicated by epigenetic indices measured in both children and adults (Aikins et al., 2024; Raffington, Schwaba, et al., 2023; Raffington, Schneper, et al., 2023).

Second, a preregistered meta-analysis of 140 studies spanning ~66,000 participants from 23 countries indicates that socioeconomically disadvantaged individuals show more accelerated and faster epigenetic aging than their more privileged peers (Figure 4; Willems et al., 2026). In studies of children, only the epigenetic pace of aging showed meta-analytically significant associations with socioeconomic status.

Third, the MPRG Biosocial has conducted a landmark preregistered study finding that children's saliva epigenetic indices respond to a randomized controlled cash gift trial: Four-year-olds whose mothers were randomized to a high-cash gift group exhibited slightly slower epigenetic pace of aging compared with children randomized to a low-cash gift group in the Baby's First Years Study (Raffington et al., 2026). These rigorously derived findings reveal that early life interventions can influence saliva epigenetic indices, even without observable behavioral differences in age-4 measures of cognition, body mass, or parental reports of behavioral problems. Ongoing research is evaluating whether these differences persist over time and whether they matter for development.

In collaboration with Emory University and the non-profit Tanzania Home Economics Association, the MPRG Biosocial is collecting saliva samples for DNA analysis from several hundred children in northern Tanzania, whose villages participate in the "Familia Bora" program. The project aims to assess the utility of epigenetic biomarkers in a low-income setting and to test their sensitivity to community co-developed parenting interventions. If validated, integrating epigenetic measures into programs that strengthen family dynamics and child development could inform social policy by providing a faster readout of the long-term effects of these interventions.

Taken together, this work supports the view that epigenetic aging and child development are intertwined, and that early-life environments have modest effects on children's epigenetic aging metrics. However, a key question remains: When epigenetic indices developed in adults are applied to children, what do they actually capture? According to Horvath's epigenetic clock theory, biological aging is an unintended byproduct of developmental and maintenance programs, whose molecular footprints give rise to epigenetic age estimators. Accordingly, in children these indices may capture the molecular imprint of early environmental exposures on later cellular functioning and/or reflect genetic influences on developmental trajectories with downstream aging consequences.

Ongoing projects are addressing this conceptual gap by mapping the overlap between existing epigenetic indices generated in adult samples with newly developed epigenetic indices of child development, including body mass trajectories and cognitive development in childhood and adolescence. These epigenetic indices will be customized to saliva samples, which are more commonly collected in child cohorts, and can help address important methodological questions of cross-tissue generalizability (Zarandooz & Raffington, 2025).

Key References

Social and Ethical Considerations in Sociogenomics

Sociogenomics holds promise for deepening our understanding of human development and life-course processes. In Germany, however, any genetically informed research must first confront the legacies of biologistic race science and ongoing racism (Aikins et al., 2024). A historically informed avoidance of genetics has not eradicated racism. Indeed, recent work documents its pervasive impact on the lives of Black German children (Aikins, Ansah, et al., 2025; Raffington, 2025).

The MPRG directly addresses these issues by reviewing sociogenomic evidence that rejects biological notions of race and advancing a race-critical biosocial framework (Aikins et al., 2024). In this framework, there is no genetic basis for discrete, socially assigned racial categories. Genetic influences are non-deterministic and transactional: they emerge through continual interplay with social conditions, and gene expression is shaped by racialized environments (Aikins, Willems, et al., 2025). This perspective challenges both genetic essentialism and race-evasive approaches, offering a way to understand how genetic effects manifest through social processes ("out of the skin") and how racism affects biology ("under the skin"). The group provides a conceptual and ethical roadmap for racism research and genetically informed research, showing how responsibly applied genomic science can help dismantle racism and advance anti-racist scholarship and social equity.

Polygenic indices show robust—albeit small and noisy—associations with complex traits and have supported scientific advances across fields. Beyond research and despite major scientific concerns, direct-to-consumer companies have begun providing polygenic health indices and offering preimplantation polygenic embryo selection for disease prevention and—even more concerning—intelligence enhancement. The regulation of these services varies widely across different countries. Moreover, polygenic genome editing may be technically possible within the next few decades. These developments underscore the urgent need to understand the developmental processes linking polygenic indices to complex traits, examine the historical and social contexts on which DNA-based biomarkers depend, and to formulate social and ethical considerations in polygenic index applications (Straub et al., 2026).

Moreover, associations between polygenic indices and complex traits vary across generations and historical contexts. This variability raises serious concerns for applications in current and future generations, including polygenic embryo selection during in vitro fertilization. Ongoing work by MPRG Biosocial is summarizing and simulating the population-level implications of such selection. Additional projects are planned to assess public attitudes toward genomic applications in Germany and Europe.

Finally, social and ethical contributions to the sociogenomics literature can be communicated to the public (e.g., the "Genetic Pinball" videogame on board MS Wissenschaft in 2024; see Figure 7) and taught in schools to reduce racial and other social prejudices, thereby promoting social equity and cohesion in the post-genomic era.

Key References

Innovation, Impact, and Knowledge Gained

The research program is innovative and impactful in the following ways:

1. Leverages a novel approach that integrates genomic data into social science designs to identify both genetic and environmental effects in intergenerational transmission. 
2. Develops and validates epigenetic biomarkers to quantify child development and its long-term reach into adulthood. 
3. Bridges distinct scientific fields by combining developmental science and epigenetics, family studies, sociology, and biosocial theory.  
4. Uses genetics and randomized trials for causal inference on genetic and social factors with high external validity. 
5. Advances validation of saliva-based biomarkers, enabling scalable, mail-based sampling in pediatric and hard-to-reach cohorts that could have clinical utility. 
6. Enhances public understanding of the environmental contingency of DNA-based biomarkers, informing potential educational and clinical applications. 
7. Fosters open science practices through data and code sharing, enabling social scientists without formal genomics training to engage critically with DNA-based research. 

Knowledge gained on the effects of genetics and social inequality on human development:

1. Racism and poverty affect the human epigenome and development in childhood. Interventions ameliorating these factors are needed to improve causal inferences and inform public policy.
2. Epigenetic indices are promising tools to study the connection between genetic and environmental influences in early life with later life outcomes. Future studies should evaluate the clinical relevance of new indices customized to samples in children.
3. Both genetics and environments are transmitted intergenerationally and contribute to social and geographic stratification in Germany. Ignoring either may exacerbate social inequality.
4. Human developmental trajectories largely remain a mystery. Behavioral and social outcomes are only minimally accounted for by current measures of genetic and environmental influences.