Board Thread:Naruto Discussions/@comment-5273810-20150830183321/@comment-734582-20150830195723

QuakingStar wrote: Although there is always a chance that the body rejects the transplanted DNA/Flesh as Orochimaru explained. Weren't there like 30 people for the Hashirama cell test alone, and only Yamato survived? Even though hokage-sanctioned research took place before that and failed too? Even Danzo had poor control over the cells.

So, i think the acquiring of specific KKG can be done, but both need to be done in sufficient amounts (Madara had only little of Hashirama's cells and so took forever to acquire the Rinnegan) for meaningful effects, and the person needs to have the skill and chakra to master them (See: kakashi is down for a week after using the Sharingan, Danzo nearly dies from Hashirama's cells, Yamato is not a great Wood Release user)