Children whose parents are thin are likely to be very slim themselves due to “skinny genes”, new research suggests.

Youngsters whose parents are at the lower end of the healthy weight range are three times more likely to be regarded as thin (weighing less than a healthy weight range) than those whose parents are overweight.

The study recorded the height and weight of parents and up to two children from 7,000 families over a five-year period.

Analysis of body mass index found that when both parents were at the lower half of the ideal BMI range, the chance of the child being thin was 16.2 per cent, compared with 7.8 per cent when both parents were in the upper half.

These children had a BMI of 18.5 or under (regarded as “thin”), compared with a healthy weight range of 18.5 to 24.9. A BMI of 25 to 29.9 is overweight and over 30 is obese.

The study found that the chance of a child being thin (BMI under 18.5) was just 5.3 per cent when both parents were overweight and only 2.5 per cent for children whose parents were obese.

Today’s study, published in the journal Archives of Paediatrics and Adolescent Medicine, suggests thinness may be inherited, with children of thinner parents being likely to be genetically predisposed to a lower body weight.