Children whose parents are obese are more likely to be obese themselves, but their mothers' genes appear to play a particularly important role in determining their weight, a new study has found.

Obesity is believed to be caused by a combination of hereditary and environmental factors. Genes passed from parents to children influence appetite, satiety, metabolism, food cravings, fat distribution in the body, and much more. 

The study, published in the journal PLOS Genetics, shows that although children receive half of their DNA from each parent, it is the mother's genetics that have a greater influence on body mass index (BMI). 

“Maternal genetics appear to play an important role in influencing a child's weight, in addition to the child's own genetics,” said Liam Wright, lead author of the study and a researcher at University College London, according to Euronews.

Wright's team analyzed genetic and medical data from more than 2,600 British families with children born in 2001 and 2002 and followed them from birth to age 17.

Access to the genes of both children and parents was a key factor. This allowed researchers to identify both the genes inherited by children and those that parents did not pass on but which could still affect their children's health. 

According to the authors of the study, these indirect effects, known as “genetic nurturing,” are significant because they help shape how children grow up, from conditions in the womb to parenting methods.

The study showed that the body mass index of both parents has an impact on the child's weight. But while the influence of fathers was almost entirely related to the genes they directly passed on to their children, the influence of the mother's BMI was more significant. 

This may be because the mother's genes influence her own weight, eating habits, or activity during pregnancy, which in turn plays a role in her child's development and health, the researchers believe.

 “Beyond the genes passed on directly by mothers, our findings suggest that maternal genetics play an important role in shaping the environment in which a child develops, and thus indirectly influence their BMI,” Wright explained. “This is not about blaming mothers, but about supporting families and making a significant contribution to the long-term health of children.”

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

According to the study's authors, efforts to help obese parents lose weight could have long-term health benefits for their children. 

“Targeted measures to reduce maternal BMI, especially during pregnancy, can reduce the effects of obesity across generations,” Wright warned.