A few years ago social scientists from the University of Minnesota, USA, compiled a remarkable database of 75 pairs of identical twins born between the mid-1930s and mid-1940s. The twins were found to have been separated at birth and adopted by separate families. At the respective ages of 40, they were re-united and each pair was given comprehensive personality tests. The scientists found that 48% of the subjects’ happiness was genetic. As a matter of fact, they found that more of each subject’s personality was genetic than they had ever understood before.

   Why, sometimes you might have encountered someone who is happy all the time, despite his uncongenial conditions. You would have wondered about the secret of his perennial equanimity. It is obvious that the secret essentially lies in his exceptional DNA. Therefore, if about half of what you are is determined by your DNA which is a constant and cannot be changed, it becomes inevitable....