A woman's risk of anxiety may depend on how stressed out her father's life was when he was young, new research has found.
A new study suggests the stress a man experiences when he is young can contribute to genetic changes in his sperm that can result in psychiatric disorders in female offspring.
And it's not only the first generation of daughters that can be affected, with the research showing the effects can last down to yet another generation.
Blame it on dad... or grandad: A study suggests the stress fathers experience as youths can be passed down to daughters in the form of psychiatric disorders
Researchers from the Tufts University School of Medicine subjected young male mice to a range of stresses by constantly changing the composition of their cages.
They found that the stresses led the mice, particularly females, to become rather more anxious and socially disfunctional than their peers who had not been subjected to stressful treatment.
The researchers then studied the offspring of these previously-stressed mice and observed that female, but not male, offspring exhibited elevated anxiety and poor social interactions.
Notably, even though the stressed males did not express any of these altered behaviours, they passed on these behaviours to their female offspring after being mated to non-stressed females.
Moreover, the male offspring passed on these behaviours to yet another generation of female offspring.
Study author Lorena Saavedra-Rodriguez said: 'The long term effects of stress can be pernicious.
'We first found that adolescent mice exposed to chronic social instability, where the cage composition of mice is constantly changing, exhibited anxious behavior and poor social interactions through adulthood.
'These changes were especially prominent in female mice.'
Co-author Larry Feig, professor of biochemisty at Tufts, added: 'We are presently searching for biochemical changes in the sperm of stressed fathers that could account for this newly appreciated form of inheritance.
'Hopefully, this work will stimulate efforts to determine whether similar phenomena occur in humans.'