In groups with high rates of posttraumatic stress disorder (PTSD), such as the survivors of the Nazi Death Camps, the adjustment problems of their children, the so-called "Second Generation", have received attention by researchers. Studies suggested that some symptoms or personality traits associated with PTSD may be more common in the Second Generation than the general population. It has been assumed that these trans-generational effects reflected the impact of PTSD upon the parent-child relationship rather than a trait passed biologically from parent to child.