Board Thread:Theories and Speculation/@comment-26422608-20150522042352/@comment-5407586-20150523205332

The problem is that Hagoromo commented that what brings forth the Rinnegan isn't Asura+Indra+Sharingan, but just Asura+Indra. Though it's true that the only ones to ever awaken the Rinnegan after Hagoromo were Madara and Sasuke, two Uchiha with Eternal Mangekyō Sharingan.