Board Thread:Naruto Discussions/@comment-25442710-20140920121351/@comment-24653630-20140922150308

As in, a descendant of Asura needs Indra's chakra or vice versa... Since Naruto is a descendant of Asura, if he somehow got Indra's chakra he could unlock the Rinnegan...

It's not exclusive to just the Uchiha.