Do the parent really give away their endowment to their children?How are the characteristics inherited?Do our inherited properties change throughout the life?If so,how do they change and by what they are changed?What are the consequences of such changes?In this chapter,we will try to get an insight as to how genetics works,some of its history and also its application. The application of the knowledge of genetics, or simply biotechnology enables scientists to achieve various breakthroughs in medical and agricultural fields.