Though a mother’s health during pregnancy can dramatically affect the health of a child, researchers have now found evidence that the health of fathers may also contribute.

A new study out of the University of Adelaide has found “molecular signals” in the sperm of obese mice fathers that could pass on obesity and/or metabolic disease to their children. This effect was found to last two generations to the mice’s grandchildren, even if the progeny were healthy eaters. The study has been published in The FASEB Journal.

“A father’s diet changes the molecular makeup of the sperm,” said Tod Fullston, lead author of the paper and a research scientist at Adelaide’s Robinson Institute. “With obese fathers, the changes in their sperm – in their microRNA molecules – might program the embryo for obesity or metabolic disease later in life.

“For female offspring, there is an increased risk of becoming overweight or obese. What we’ve also found is that there is an increased chance of both male and female offspring developing metabolic disease similar to type 2 diabetes.”

According to Fullston and his colleagues, even mice fathers who were obese but did not show any signs of diabetes were found to pass on the risk of this metabolic disease down to two generations. Though the obesity seen in the second generation was not as “severe” as the first generation of offspring, these results were found regardless of the eating habits of either generation.

“If our laboratory studies are translatable to humans, this could be a new and as yet unexplored intervention window into the epidemic of childhood obesity,” said Fullston. “A focus on the mother’s health is extremely important, but we’re seeing that the father’s health is also important for conception. It’s possible that by showing additional attention to diet and exercise in the father, this could have a positive impact on his future children and grandchildren.”