For years social anxiety disorder (SAD) has been thought to be caused from environmental circumstances. Recently there has been a lot of research to determine if there are any genetic causes of social anxiety disorder. Genetic and family studies in SA are still in their infancy, but there has been much progress made. SA is a relatively new disorder, it was discovered in 1980. Even though most people are unaware that this disorder exists, SAD is the third most common psychiatric disorder, preceded only by depression and alcoholism according to the Medical Research Council on SAD.To date studies on the relationship between genetics and social anxiety disorder have been inconsistent. However, studies with animals are providing evidence that suggest SA can be inherited. In recent research, supported by the National Institute of Mental Health (NIMH), researchers have been able to identify the site of a gene in mice that affects learned fearfulness.There are also many researchers that conclude that there are genetic causes of social anxiety disorder. Many children will have a parent or both parents with an anxiety disorder, not necessarily social anxiety disorder. They believe the child inherits certain traits of their parents Behavioral Inhibition. Behavioral Inhibition is basically a pattern of behavior involving withdrawal, avoidance, fear of the unfamiliar, and a tendency to react negatively to new situations or things. Studies show that these inherited traits lead to the development of SAD in adolescence.Jerome Kagan, PH.D, a researcher at Harvard, has conducted studies on the genetic causes of SAD. The results of his study of children from infancy to adolescence concluded that “10-15% of children to be irritable infants who become shy, fearful and behaviorally inhibited as toddlers, and then remain cautious, quiet, and introverted in their early grade school years. In adolescence they had a much higher than expected rate of SAD.” This evidence suggests that people are born with SAD or with traits that will more than likely lead to its development. Kegan also uncovered a common physiological trait in his study group; they all had a high resting heart rate, which climbed even higher in stressful situations. This is another indicator that there is a link between genetics and social anxiety.Of course there may be other factors that contribute to the development of SAD, such as psychological modeling or environmental circumstances, however the evidence that supports the genetic causes is getting stronger. Research has also concluded that people who have SAD are likely to have a family member with social anxiety as well.