Stressed fathers ‘pass on mental illness to unborn’
MEN experiencing stress could father children with a greater risk of developing mental illness, research suggests.
Even mild stress can cause damage to a man’s sperm which triggers biological changes in his offspring, the study showed.
In tests on mice, abnormal reactions to stress were seen in the offspring of their stressed fathers.
Mild stress was created by the researchers in the father mice by placing them in a tube – where their levels of stress hormones were closely measured.
The offspring fathered by the ‘stressed’ mice were later placed in similar stress situations – and were found to have lower levels of the stress hormones.
This so-called ‘blunted’ hormonal response has been found in people who develop a variety of mental disorders, including post-traumatic stress disorder and autism.
Scientists believe the stress on the father temporarily affects the DNA in his sperm. Putting the mice in fraught situations caused molecules known as microRNA to be released. These micro-RNA switched off the genes in the DNA of the father’s sperm responsible for producing stress hormones.
This led to the baby which was born from the affected sperm having impaired responses to stress.
The offspring were more susceptible to the conditions, such as PTSD, that are associated with this hormonal shortage.
It has long been known that a mother’s condition during pregnancy can harm her child – with damage caused by factors such as poor diet, stress or infection.
But the latest research highlights how a father’s health at the time of conception can also can have an impact.
The findings are important because they show how changes in environment can be passed on to future generations.
Speaking at the 2018 AAAS annual meeting in Austin, Texas, US, yesterday, Professor Tracy Bale, from the UniProfessor versity of Maryland, said: ‘The findings were fascinating and very surprising.
‘We dealt very mild stress to the dads. I would not equate it to trauma, but mild chronic periods of stress – the type all of us experience in our lives.
‘This effect lasts a very long period. We have not been able to review the animals long enough that the effect is washed out.’ Bale’s research suggests that even mild environmental challenges can have a significant impact on future offspring.
She said: ‘We now know Dad’s stress is ultimately reprogramming his offspring’s stress levels.’
Professor Bale said the offspring of a stressed male would have a ‘dampened’ stress reaction, but that too much dampening can be linked to the development of psychological disorders.
She said one application of the research could be to screen the sperm of soldiers returning from war.
By learning more about the links between a father’s exposure to stress and the risks of disease for his offspring, we can better understand and prevent these disorders, Professor Bale added.
Research has traditionally focused not on fathers, but on the well-being of pregnant mothers and women planning a pregnancy.
Babies’ responses can be impaired