A new UK study has found that mothers’ genetics may play a stronger role than fathers’ in determining a child’s risk of becoming overweight, which is a significant factor in understanding obesity. Led by researchers at University College London (UCL), the study introduces compelling evidence for a concept known as genetic nurture—where parents’ genetics indirectly shape their children’s health environment.
The study was published in the journal PLOS Genetics. It analysed data from 2,621 families. This was part of the Millennium Cohort Study, a long-term UK project following children born in 2001 and 2002.
Study Examined Child BMI from Birth to Age 17
Researchers focused on the impact of parental body mass index (BMI) and genes on children’s weight. They also examined how it affected diet and development across six age milestones. Children were assessed at ages 3, 5, 7, 11, 14, and 17. Their BMI, birthweight, and dietary habits were evaluated through self-reported food consumption surveys.
These surveys tracked the frequency and quantity of various food groups including fruit, vegetables, fast food, and sugary drinks. Dr Liam Wright, the study’s lead author, noted that this approach allowed them to map long-term weight trends in relation to parental influence.
Genetic Nurture Explains Mother’s Continued Influence
The research team was able to separate the effects of inherited genes from those not inherited. This distinction is crucial for understanding indirect genetic effects. They found that both parents’ BMI correlated with their child’s weight. Still, only the mother’s BMI showed long-term influence beyond what was inherited.
Father’s influence was primarily genetic. The mother’s impact extended beyond genetics. This suggests that maternal behavior and environment played a significant role.
This supports the idea of genetic nurture: a parent’s genes can shape their child’s development indirectly, by influencing womb conditions, early feeding practices, and dietary habits.
“Mothers’ genetics seem instrumental in shaping the child’s environment,” said Dr Wright. “This affects their BMI even beyond what they inherit.”
Maternal BMI May Influence Pregnancy and Childhood Environments
Researchers suggest that maternal BMImay affect pregnancy health, as well as early-life nutrition and behavioral patterns that promote weight gain in children. These could include eating habits during pregnancy, food choices at home, or modelled behaviours around diet and exercise.
A mother with high BMI might unknowingly create an environment where unhealthy eating habits become normalized, contributing to a child’s long-term risk of obesity.
“This isn’t about blaming mothers,” Dr Wright stressed. “Rather, it’s about understanding how we can support families to improve child health.”
Study Used Additional Measures Beyond BMI
While BMI is commonly used in obesity research, it is not a perfect indicator of body fat, especially in growing children.
To strengthen their findings, the UCL researchers supplemented their analysis with adiposity-related measures, such as fat mass, which provide more accurate insight into body composition.
This multi-dimensional approach confirms that the influence of maternal genetics persists across various health metrics, reinforcing the importance of maternal health in childhood development.
Implications for Public Health: Interventions Should Focus on Maternal Health
With childhood obesity on the rise, this study highlights a new avenue for intervention—targeting maternal health, particularly during pregnancy.
UK NHS data from 2024 shows that 27% of children aged 2 to 15 are considered overweight or obese, underscoring the need for urgent action.
By addressing maternal BMI and health habits, public health campaigns may reduce intergenerational transmission of obesity and improve long-term outcomes.
“Supporting mothers before and during pregnancy may be key to reducing childhood obesity,” Dr Wright concluded.
What Is Genetic Nurture?
Genetic nurture refers to the way a parent’s genetics can influence their child’s development indirectly, by shaping the home environment.
For example, a mother with genes that predispose her to obesity may pass on these genes directly. However, she may also create an environment—through lifestyle, diet, and routines—that further reinforces unhealthy patterns in her child.
This dual influence means that genetic and environmental factors work together, complicating the traditional nature vs. nurture debate.
The study’s findings give weight to this emerging concept and suggest policy-makers and healthcare providers consider it in future obesity interventions.
Key Takeaways from the Study
- Mother’s genetics had a stronger influence on children’s long-term weight compared to the father’s, due to genetic nurture.
- Father’s influence on BMI was explained almost entirely by inherited genes, not the environment.
- Maternal BMI was linked to child BMI even after accounting for inherited genes, suggesting environmental and behavioral factors were at play.
- Addressing maternal health, especially during pregnancy, could significantly reduce childhood obesity risks.
- The study stresses support over blame, aiming to provide insights for more effective family-centered interventions.
Final Thoughts: Supporting Maternal Health Is Crucial to Tackling Obesity
This study adds to growing evidence that mothers’ health behaviors and genetics have long-term consequences on children’s weight and well-being.
Rather than placing blame, the findings offer an opportunity to design targeted strategies for maternal support—through education, nutrition programs, and prenatal care.
As childhood obesity continues to rise globally, understanding its genetic and environmental roots is critical to curbing the trend.
Helping mothers manage their health may be the most impactful step toward healthier families—and a healthier next generation.