A study of twins found that genetic variants associated with obesity appeared to account for 43% of body-size difference in children at age 4 and 82% of the difference at age 10. "Our results demonstrate that genetic predisposition to obesity is increasingly expressed throughout childhood. ... This underlines the importance of intervening at an early age to try to counteract these genetic effects and reduce childhood obesity," said study co-leader Dr. Clare Llewellyn. The findings were published in the journal Obesity.