S uccess of cloning depends solely on how much we may know about spirit and its role on physical bodies. Right now, we have not got a clue if the body is an independent entity, or if at all can function without having spirit. We have found that brain dead can not function as an active physical entity. Again we don't know if the functionalities of a brain is in anyway connected to having spirit present. Although we may not know for sure at this time if we would be able to clone the physical body successfully, we could make an educated guess that we may be able to do such things in the future.
Question remains as to how to guarantee the presence of spirit at the same time.
This very dilemma dictates that we do more research on spirit at the same time while we are trying to clone humans, at least before actually attempting to clone physical bodies. There are some hypothetical situations we may consider in order to evaluate the pros and cons of cloning. It may not be worthwhile to clone just for propagation. May be, but all geniuses have mediocre physical bodies. Special capabilities of their brains made them geniuses, and again we do not know for sure if physical brains or the presence of the spirit made the brains capable of thinking at higher levels.