Recent studies suggest that sperm not only carries genetic makeup but also genetic code of the father's weight, and this encrypted code can potentially be passed on to the offspring leading toward obesity. One of the well-known inheritable disorders is obesity especially with children whose fathers are obese or have high risk for obesity.

However, not all those fats can be blamed to genetics alone. Factors such as lifestyle and environment can contribute epigenetically. This means that these influence how genes are expressed.

"We did not expect to see such important changes in epigenetic information due to environmental pressure," lead author Romain Barrès said. "Discovering that lifestyle and environmental factors, such as a person's nutritional state, can shape the information in our gametes and thereby modify the eating behaviour of the next generation is, to my mind, an important find."

The team comparatively studied the sperms of 10 obese and 13 normal weight men. They found significant differences between the genes expressed by the two groups. They also studied men who underwent gastric bypass surgery where there are remarkable changes between the presurgery and 1 year postsurgery phases. They found "dramatic remodeling" where remarkable epigenetic markers were noted in the sperm cells after operation.

Other studies also claimed that modifications transfered by mothers. Furthermore, another circumstance was also presented. For instance, well-being of grandchildren of people who lived during the famine revealed a heightened risk for cardiovascular diseases. The variation may be pointed to the epigenetic modifications. However, this recent research outlays the molecular switch in fathers.

"Today, we know that children born to obese fathers are predisposed to developing obesity later in life, regardless of their mother's weight," another lead author Ida Donkin said. "It's another critical piece of information that informs us about the very real need to look at the pre-conception health of fathers. And it's a message we need to disseminate in society."