Do genes determine our traits? At one time, researchers believed that genes played little role in determining our personality. Today, DNA analysis suggests that genetic influence may be very important. Although our genes may play a more important role in some traits than others, so far research indicates that there is some genetic influence on every trait. Studies of twins raised apart suggest that genes may even play a role in criminality and addiction. Such understandings are not politically popular. Eventually, the research findings may call us to revise our comfortable views of human nature. Having completed sequencing the human genome, researchers now turn their attention to the role that genes play in a variety of specific human characteristics. Application of this research will become increasingly important. One project is aimed at understanding the genetic basis of depression. By comparing the genetic code of depressed persons with that of non-depressed persons, researchers aim to uncover the specific genes involved in depression. In addition, researchers are studying the possible genetic influence on antisocial behavior. Hopefully, findings will eventually enable them to identify children who are likely to develop problems. The research raises the question of whether we will eventually need to view antisocial behavior as an illness like schizophrenia or depression. Medical intervention may be able to prevent problems before they occur. Similar efforts are underway to understand the possible genetic basis of alcoholism and other addictions. Some believe that thrill-seeking may be an important factor in such disorders. From this research we may eventually learn how to intervene most effectively in treating addiction.