ROTJ represents the origin of such theories, that's for sure. SW '77 and ESB '80 do not suggest any more than that Luke is inspired to become a Jedi by the memory of his father. The openness of Yoda's teaching in ESB has been undermined by developments from ROTJ onwards, in my opinion. The proposition of Luca$h's saga, that ability to use the Force is primarily determined by your genome rather than your commitment and willingness to learn, is a poorer one, I think.