If you are planning a baby, do not just sermon your wife to eat well but control your diet first. According to a fascinating study, sperm carries key information about what new dads gulped down before the conception.
It turned out that dads are also eating for two, say researchers, revealing that a man's weight affects the heritable information contained in sperm.
"It is common knowledge that when a woman is pregnant she should take care of herself - not drink alcohol, stay away from pollutants, etc. But if the implication of our study holds true, then recommendations should be directed towards men too," explained senior study author Romain Barres, associate professor at University of Copenhagen.
The sperm cells of lean and obese men possess different epigenetic marks, notable at gene regions associated with the control of appetite.
The initial study which included 13 lean men and 10 obese men offered one biological explanation for why children of obese fathers are themselves more predisposed to obesity.
In the next phase, the investigators tracked six men undergoing weight-loss surgery to see how it affected their sperm.
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An average of 5,000 structural changes to sperm cell DNA were observed from the time before the surgery, directly after, and one year later.
"More needs to be learned about what these differences mean and their effects on offspring, but it is early evidence that sperm carries information about a man's health," the authors noted.
"Our research could lead to changing behaviour, particularly pre-conception behaviour of the father," Barres pointed out.
During the study, Barres and colleagues compared specific epigenetic marks in the ejaculate of lean and obese men.
There are likely evolutionary reasons why information about a father's weight would be valuable to offspring.
To learn more about the epigenetic-offspring connection, Barres' lab is now collaborating with a fertility clinic to study epigenetic differences in discarded embryos generated from the sperm of men with various degrees of body weight.
"It is clear that these epigenetic changes happen in mice and rats but we also need to know if this also happens in humans and whether this is a significant driver for changing our traits," the authors concluded in the journal Cell Metabolism.