Father's age and lifestyle could impact health of children
A father's age, behaviour and living conditions have largely overlooked genetic effects that can harm the health of his children and possibly their offspring as well, say scientists.
Researchers conducted a review of all the available evidence on so-called epigenetic environmental effects that alter the activity of inherited genes passed on by men.
They found a host of examples where a father's age, lifestyle and experience can lead to lifelong physical and mental problems in his children.
Advanced age when conceiving, for instance, was associated with raised rates of schizophrenia, autism and birth defects.
Paternal obesity was linked to enlarged fat cells, metabolic changes, diabetes and a propensity to put on weight, and an increased risk of brain cancer.
Fathers who drank too much alcohol risked having lighter children with smaller brains and impaired mental skills, while those affected by stress passed on a susceptibility to defective behavioural traits.
US senior investigator Dr Joanna Kitlinska, from Georgetown University Medical Centre in Washington DC, said: "We know the nutritional, hormonal and psychological environment provided by the mother permanently alters organ structure, cellular response and gene expression in her offspring.
"But our study shows the same thing to be true with fathers. His lifestyle, and how old he is, can be reflected in molecules that control gene function. In this way, a father can affect not only his immediate offspring, but future generations as well."
She pointed out that newborn babies can be diagnosed with foetal alcohol spectrum disorder (FASD) - a wide range of problems normally associated with drinking during pregnancy - even though their mothers had never touched alcohol.
"Up to 75% of children with FASD have biological fathers who are alcoholics, suggesting that pre-conceptual paternal alcohol consumption negatively impacts their offspring," Dr Kitlinska added.
Epigenetic effects alter DNA activity without rewriting the genetic code. In many cases, genes are "silenced" by subtle molecular changes to DNA components.
There is increasing evidence that such effects can be passed from one generation to another.
The new research, published in the American Journal of Stem Cells, found one advantageous result linked to a father's diet.
A Swedish study found that men whose food intake during their own childhood was restricted had children and grandchildren with a reduced risk of dying from heart disease.
"This new field of inherited paternal epigenetics needs to be organised into clinically applicable recommendations and lifestyle alterations," said Dr Kitlinska. "And to really understand the epigenetic influences of a child, we need to study the interplay between maternal and paternal effects, as opposed to considering each in isolation."