Stress can cause permanent damage to a man's sperm and even stunt his children's brain development, a new study has found. Researchers have discovered that suffering anxiety or depression as an adult, teenager or even as a child could cause a lasting genetic change in a man's sperm. Scientists conducting a study on mice found that sperm damage caused by stress leads to offspring developing a 'blunted reaction to stress' - a trait associated with several mental disorders. Researchers at the University of Pennsylvania School of Medicine say this is the first time a link has been found between stress-related diseases potentially being passed from a father to his children. Previous studies have concentrated on how environmental challenges - such as diet, drug abuse, and chronic stress - felt by mothers during pregnancy can affect their offspring's neurodevelopment and increase the risk of certain diseases. In this study, published in the Journal of Neuroscience, m