The concept of gene therapy has long appealed to biomedical researchers and clinicians because it promised to treat certain diseases at their origins. In the last several years, there have been several trials in which patients have benefited from gene therapy protocols. This progress, however, has revealed important problems, including the problem of insertional oncogenesis. Gene therapy research and eventual therapeutic use are governed by the fundamental ethical principles which are autonomy, beneficence and non maleficence, the principle of Justice and the principle of Freedom of Research. Application of somatic gene therapy seems to be morally accepted. However, application of germ line gene therapy is accompanied from its beginning by intense ethical, religious, and political debates.