The children of obese mothers are far more likely to develop diabetes than those with thinner mums.
An international study led by Dr Matt Sabin from the Murdoch Children's Research Institute in Melbourne has found that a mother's body mass index (BMI) can be used to predict whether a child will develop type 2 diabetes.
The researchers studied 1800 kids over a period of 20 years, recording their diets, exercise, family history, genetics and the BMI of their mother and father.
The mother's BMI was found to be the most accurate predictor of whether the child would develop diabetes, while the father's BMI was irrelevant.
When a high maternal BMI is combined with a high BMI in the child, the risk of diabetes in the child skyrockets.
Dr Sabin said the research could help identify children who were at high risk of the condition so doctors could intervene and possibly prevent the condition from developing.
Early intervention is all about a healthier lifestyle, something Dr Sabin coaches parents on at the obesity clinic he runs at Melbourne's Royal Children's Hospital.
He says getting a child's weight under control early could change their whole medical future, and the future of their children too.
"Once you're an overweight adult, your body really defends your weight," Dr Sabin told The Weekly.
"It's the classic yo-yo cycle. They go on a diet, do it for a period of time and then when they give up their body basically sucks back all that weight and usually a bit more.
"But young children are a little bit more malleable. It may well be that interventions will be able to change their weight trajectory. And that's really exciting because it means is that it's not a preordained destiny for these children to become bigger than their parents."
Type 2 diabetes can lead to blindness, amputations, kidney failure, heart disease and death.
Dr Sabin's research has been published in the current issue of the Journal of Pediatrics.