Every year many genes that lead to medical disorders are discovered. Germ line therapy may be able to help cure these diseases in the present population and eradicate it from future generations. Adult body cells are much more abundant than embryonic cells, and no fetuses are sacrificed to make new tissue. Only the original colonies of stem cells, which are already in existence, need to be used for future organ cloning techniques. Germ line therapy is also simpler that somatic cell therapy.
Cloning is more accurate in an embryo than microinjection.
In microinjection, naked DNA is injected into the nucleus of a fertilized egg. The downside of this type of therapy is that it is very new in humans and has yet to be perfected. The vector DNA would also incorporate into the cell DNA and become a part of the host DNA in all cells in the body. Other concerns are that somatic cell therapy has never produced a clinical success. Harmful mutations may occur and be passed on to future generations.