You underestimate the dificulty of changing the genome in every cell in the body. Remember, your body fights off colds with a lot of succsess, the 'symptoms' of a cold are actualy your own body fighting it off not changes made by the cold. The body also attacks cells that are diferent from the 'normal' cells in that body. And the cases where it fails to do so usualy result in cancer type growth.
Genetic therapy is infact only feasable in young children who are growing new cells at a fast rate. And even then it is still plauged with problems. Recent trails on a simple gene therapy were halted after it resulted in lukemia.
Escentialy, the problem is that just because you 'grow' a new type of cell structre in a body by modifiation of the genome, it dosnt mean that the body wont react in just the same way as if you implanted it as foreign material.
And thats even before you get to the problem of having cells form into their discrete organ structures. We dont even know how that happens naturaly, let alone replicating it scientificaly. (PS. The famious 'Mouse with a Human Ear' was infact a cartalage graft, the mouse did not grow the human ear.)
You underestimate the dificulty of changing the genome in every cell in the body. Remember, your body fights off colds with a lot of succsess, the 'symptoms' of a cold are actualy your own body fighting it off not changes made by the cold. The body also attacks cells that are diferent from the 'normal' cells in that body. And the cases where it fails to do so usualy result in cancer type growth.
Genetic therapy is infact only feasable in young children who are growing new cells at a fast rate. And even then it is still plauged with problems. Recent trails on a simple gene therapy were halted after it resulted in lukemia.
Escentialy, the problem is that just because you 'grow' a new type of cell structre in a body by modifiation of the genome, it dosnt mean that the body wont react in just the same way as if you implanted it as foreign material.
And thats even before you get to the problem of having cells form into their discrete organ structures. We dont even know how that happens naturaly, let alone replicating it scientificaly. (PS. The famious 'Mouse with a Human Ear' was infact a cartalage graft, the mouse did not grow the human ear.)