Girls are more likely to grow up to become dangerously overweight if their mums are, according to a study.
It found that for every 100 mums who were obese, 41 of their daughters were too. When they looked at 100 healthy mums, only four girls were obese.
It was a similar story with overweight dads and their sons, but obese mums didn't lead to overweight sons and dads who were obese didn't have obese girls.
Experts say it shows weight problems aren't inherited, they're learnt.
The researchers at a medical school in Plymouth studied 226 families.
Their research included measuring the weight of the children when they were born, which showed that the obese kids didn't start out any heavier than their friends.
That meant they got heavier than their friends as they grew older.
The researchers are convinced that the obese children are learning behaviour that makes them obese, rather than inheriting being overweight from their parents.
If that was the case, overweight mums would be as likely to have overweight sons as daughters, which isn't what happened in the study.
The researchers say this proves it's really important to teach adults about healthy living, so their kids can learn from them.