Board Thread:Theories and Speculation/@comment-45986362-20200731113944/@comment-1458758-20200801144302

Well not just unique abilities, otherwise every technique used by only one person would be a KKG, it's explained by Kakashi pretty damn early that KKG have a genetic component, so even if you have an ability like the Sharingan, unless you possess that genetic component as well, you won't be able to duplicate those abilities.

Just to be clear, I'm not saying that WR is a Senju KKG, it's still only Hashirama who through whatever genetic lottery was the only one to unlock the ability naturally, but this doesn't mean that it would be impossible for his descendents or those related to him to gain the same ability.