Human beings are exceedingly assorted. In general variation is due to genetic differences. Individual differ from one another in their normal physiological and mental attributes. Variations can be normal or abnormal. They also differ in their susceptibilities for particular disease or other abnormalities. These variations are due to genetic as well as environmental factors. There is strong evidence that genetic factors play an important role in human diseases. In the technologically developed countries, genetic disorders and birth defects are emerging as a major health problem, especially after eliminating malnutrition and endemic diseases, and having better control over epidemic and environmental disorders. In this paper ...