gallifreyan99 writes "Scientists have spent decades trying to understand and fix social problems like violence and alcoholism, usually focusing on the poor and disadvantaged. But now a small band of researchers is claiming that biology plays a vitally important role — because trauma can change you at a genetic level that gets passed on to kids, grandkids, and perhaps even beyond."
Part of the research involved testing the effect of stress on the genetics of mice. A number of mice were subjected to stressful situations and then allowed to raise their children. The children, when later subjected to stress, were more vulnerable to it than normal mice (for example, they would stop struggling in a potentially fatal situation earlier than 'happy' mice). This was expected. What's interesting is that when those children were later bred with normal mice, and that third generation was raised by normal mice (so that parental neglect wasn't a factor), they still showed the same vulnerability to stress. A subsequent generation showed the same.