Parents are being offered a way to predict the chances of their newborn baby becoming obese.
The online prediction is based on factors including the baby's birth weight, the body mass index (BMI) of its parents, and the number of people in the household.
Also taken into account are the mother's professional status and whether she smoked during pregnancy.
Researchers hope the formula will help identify infants at high risk of obesity, and assist families.
Childhood obesity is a leading cause of early type 2 diabetes and heart and circulatory disease, which is becoming more common in developed countries.
Around 17% of boys and 15% of girls aged two to 15 in England are now classified as obese, according to NHS figures.