Traumatic events leave their mark. People exposed to a traumatic experience early in life are more likely to be affected by illnesses such as borderline personality disorder or depression. However such experience can also have positive effects in certain circumstances. Thus, moderate stress in childhood may help a person develop strategies to better cope with stress in adulthood. Further, it has long been recognised by psychologists and psychiatrists that the negative effects of trauma experienced by parents can be seen in their children, but the molecular mechanisms underlying such transmission are only beginning to be identified. A research team led by Isabelle Mansuy, Professor of Neuroepigenetics at the University of Zurich and ETH Zurich, has for the first time tested in mice the degree to which the beneficial effects of stress can be passed to following generations.