Researchers, led by Struan Grant, the Associate Director of the Center for Applied Genomics at the Children's Hospital in Philadelphia, have potentially identified two genes that may increase the risk of childhood obesity, however the team warn that it is only one piece of the puzzle and that these genes do not fully explain the problem. The results of the study will be published in the journal Nature Genetics.

The two genes, OLFM4, found on the 13th chromosome and HOXBX, found on the 17th chromosome are thought to increase the risk of childhood obesity by setting off a chain reaction in the body when certain other factors are present. Researchers found the two genes by looking at the data from fourteen studies all completed in North America, Europe and Australia. Over five thousand obese children and over eight thousand normal weight children were involved in those studies.

Scientists have been trying to link genetics to some cases of childhood obesity for years, saying that in some cases it would almost seem impossible to ignore that possibility. For example, they said, two children being fed the same diets and getting the same exercise should be the same weight but that is not always the case. For some kids, the risk of becoming overweight is just too great, so special treatment might be necessary.

Critics of the study claim it is nothing more than an attempt at rationalization, a way to shift the blame of childhood obesity away from the parents, fast food and poor quality school lunches. But the researchers were quick to address that criticism saying that they know that these genes are completely responsible for obesity, however they may show that some people just have a higher risk of gaining weight under conditions where another person may not.

Most experts agree that childhood obesity, which affects a rising number of American children, is a combination of many factors including their diet and their environment. Another study has shown that children who are being raised by at least one obese parent is already at risk for being at a high weight themselves and that the risk doubles for children with both parents overweight. Weight issues for children may be recognized from infancy with some children gaining weight very rapidly from the time they are infants. Others may be normal weight until they hit puberty and then suddenly gain weight. It is important, researchers say to determine what role these genes actually play so that a proper plan can be devised for treating these children and preventing them from becoming obese.