We know for sure that a woman’s health before and during pregnancy has a powerful influence on the health of her children not only in their earliest days but throughout their entire lives. Mothers with gestational diabetes may have children who are predisposed to obesity and abnormal glucose metabolism as well as elevated risk factors for cardiovascular disease. From a poor diet to disrupted circadian rhythms to exposure to stress hormones in utero a woman’s physiological and psychological states can have profound effects on the lifelong wellbeing of her children. But what about a man’s health? Can a father’s health affect his children too?

Considering fathers provide half the genetic material for their offspring it stands to reason that a man’s health would have an influence on that of his children. And yet can one cell—a single sperm cell which is a tiny fraction of the size of an egg—still induce effects while a developing baby spends nine months quite literally “marinating” in the nutrition and hormones provided by its mother? A 2015 study out of McGill University suggests yes it can.

The study which was conducted on mice indicates that paternal cellular material—specifically histone proteins—affects development and subsequent health of offspring for at least two generations. So for a glimpse at one’s health history looking to fathers is helpful but don’t forget about grandfathers. (Unless grandpa was one of those outliers who smoked like a chimney drank like a fish and died in his sleep with a smile on his face at 98 years old!)

Researchers chemically altered male mice’s histones in order to simulate certain environmental exposures. They found the offspring were prone to birth defects abnormal skeletal formation and had reduced survival rates across the two generations that were studied. (Had the study looked at subsequent generations the effects may have persisted.)

Histones do not transmit genetic information but they are a crucial structural factor for the proper organization of DNA inside cell nuclei. Acetylation and deacetylation of histone proteins serve to regulate gene expression and influence cellular proliferation development and differentiation. Irregular or aberrant acetylation and deacetylation have been linked to fragile X syndrome various cancers and a host of neurodegenerative conditions including Huntington’s disease Alzheimer’s disease and amyotrophic lateral sclerosis (ALS).

Histones are subject to epigenetic influences—diet sleep stress environmental exposures—so it’s possible that compromised paternal histone proteins could have an adverse effect on offspring development and long-term health. “Post-translational modifications that occur on certain amino acid residues of the tails of histone proteins modify chromatin structure.” Modified chromatin structure in turn may influence gene expression. Histone deacetylase inhibiting drugs are being investigated precisely for this reason.

Coming at this from another angle there are other effects imparted by paternal health upon offspring. A Danish study found that children born to older fathers had an increased risk of schizophrenia mental retardation and autism spectrum disorders. Other studies support this potential link between paternal age autism spectrum disorders and other psycho-social conditions in male children as well as increased risk for neurocognitive developmental delays. Children of older fathers—40 years old and above—have an increased risk of dying during their first five years of life with the highest risk of death found among children whose fathers were 45 or older. It has long been recognized that maternal age is a powerful influence on the development and health of offspring but it’s becoming increasingly recognized that “men of a certain age” may want to take these issues into account when deciding whether or not to have a family.

Maternal diet is of course a profound factor on the development and lifelong health of a child. But fathers aren’t off the hook where nutrition is concerned. Paternal obesity can have detrimental effects on offspring via genetic and epigenetic changes to sperm. Fortunately evidence suggests that interventions intended to reverse obesity and improve metabolic health prior to conception may normalize detrimental epigenetic changes to sperm resulting in better metabolic health in offspring.

Bottom line: Just because babies spend nine months inside their mothers doesn’t absolve fathers of their responsibility to be healthy and well-nourished prior to conception.