It has long been common knowledge that a mother's behavior during pregnancy can have an impact on the health of her unborn child. But a new branch of science is now suggesting that that epigenetic factors in a father's life — such as consequences of traumas, diseases he once had, and even foods he ate — can have an impact on the health of future offspring as well, even if these behaviors and events took place long before the time of conception.

A recent New York Times article discussed these findings, and received an enormous response from expectant dads. Dr. Dolores Malaspina, a professor of psychiatry at New York University, researches this phenomenon, and says that more and more evidence has shown that it is not just the sequence of DNA that is passed on to our children. "There's this other source of information for the lived experiences of mom and dad, even before the offspring was a fused sperm and egg." The evolutionary reason for this is that the child is being "best fit" for the environment it is likely going to be born into. Epigenetic mechanisms can turn genes on and off, in order to make the fetus better-suited to the environment of his or her parents.

Erik German, an expecting father, is a bit worried about some of his own past behaviors. "I was a pretty enthusiastic cigarette smoker in college," he says, and though his wife was taking vitamins "like crazy" before their pregnancy, he was not. But Dr. Malaspina says this research should not be cause for panic among expecting parents — the news isn't all bad. "Because we study diseases, we pick those up, but perhaps some of the gifted and most individually capable creative thinkers have also had parents with unusual exposures."