Obesity is a metabolic disease that originates not only from behavior but also from inherited genetic material. Children of obese men develop metabolic disorders and diseases regardless of the mother’s weight, according to a study in the journal Cell Metabolism. Prof. Romain Barres from Denmark’s University of Copenhagen was inspired by an older study that focused on the nutrition of a group of people. According to the study, the food access of these people during World War II had a visible relationship with the likelihood of developing cardiovascular disease in their grandchildren 60 years later. This was one of the first indications of the idea that nutritional stress experienced by an organism can be transmitted to its offspring through the so-called epigenetic markers. These markers can be micro RNA molecules, chemical additives to proteins supporting the function of DNA or methyl groups changing the very structure of DNA upon contact. Markers can influence the way genes are expressed (transition from information to implementation and into protein production). Barres and colleagues compared specific markers in the ejaculate of 13 lean and 10 obese men. The sperm of lean and obese men contained different epigenetic markers, especially those related to appetite control. Methylation of genes related to brain development and appetite was also observed in obese men. NEWS_MORE_BOX To determine whether these differences were indeed due to obesity, the scientists followed the effect of bariatric surgery on sperm epigenetics in 6 men. An average of 5,000 of their sperm were analyzed before, immediately and one year after weight loss surgery. Their results confirmed the theory that body weight is an important factor in epigenetics. Scientists believe that DNA in sperm carries specific information about a man’s health. They hope that such findings will prompt obese men, especially those considering fatherhood, to take care of their weight: this will lower the likelihood of cardiovascular and metabolic diseases both for them and for their children and grandchildren.