Board Thread:Naruto Discussions/@comment-33156423-20170923231447/@comment-6769189-20170926203931

Judging from the definitions anf the story of Kaguya, humans had the 2 energies but couldn't mix them to create chakra. The Shinju/Juubi/ granted that ability and Hagoromo portioned some chakra out, possibly granting the ability with that portion