Published on
06/08/2025 – 6:00 GMT+2


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Children with obese parents are more likely to be obese themselves – but their mothers’ genes appear to be particularly important in determining their weight, a new study has found.

Obesity is thought to be caused by a combination of hereditary and environmental factors. Genes passed from parents to children affect people’s appetite, sense of fullness, metabolism, food cravings, body fat distribution, and more.

The study, published in the journal PLOS Genetics, indicates that while children get half of their DNA from each parent, it’s the mother’s genetics that matter more when it comes to body mass index (BMI).

“Mothers’ genetics appear to play an important role in influencing her child’s weight over and above the child’s genetics,” Liam Wright, the study’s lead author and a researcher at University College London, said in a statement.

Wright’s team analysed genetic and health data from more than 2,600 UK families with children born in 2001 and 2002, tracking them from birth to age 17.

Having access to both the childrens’ and parents’ genes was key. It enabled researchers to identify both the genes that kids had inherited as well as the genes that parents did not pass down – but that might still influence their children’s health.

Those indirect effects, called “genetic nurture,” matter because they help shape how children grow up, from conditions in the womb to parenting practices, the study authors said.

Both parents’ BMI matter when it comes to a child’s weight, the study found. But while the fathers’ influence was almost entirely related to genes he had directly passed down, the impact of the mother’s BMI went further.

That could be because a mother’s genes influence her own weight, eating habits, or activities during pregnancy, in turn playing a role in her child’s development and health, the researchers said.

“In addition to the genes mums directly pass on, our findings suggest that maternal genetics are instrumental in shaping the environment in which the child develops, therefore indirectly influencing the child’s BMI too,” Wright said.

“This isn’t about blaming mothers, rather, supporting families to make a meaningful difference to children’s long-term health,” he added.

Other research has shown that fathers who were overweight or obese at the time of conception are more likely to have children with obesity.

Efforts to help obese parents lose weight could have long-lasting health effects for their children, according to the study authors.

“Targeted interventions to reduce maternal BMI, particularly during pregnancy, could reduce the intergenerational impacts of obesity,” Wright said.