J.J. Abrams' Star Wars: Episode VII - The Force Awakens will certainly have to pull out all the stops if it wants to please the famously protective Star Wars fans. For one thing, he'll have to navigate the narrative minefield left by the prequel trilogy.
Among many of the controversial and now canonical story elements introduced in the prequel trilogy was the midi-chlorians - an apparently scientific explanation for the mysterious 'Force.' Until the prequel trilogy, the Force was never fully explained, instead it seemed to be a strange supernatural, maybe even quasi-religious, phenomenon. Now it appears to be the result of what Simon Pegg once labelled a 'blood condition.'
In a recent red carpet chat for Mission: Impossible: Rogue Nation, MTV's Josh Horowitz asked J.J. Abrams if they'd also be making an appearance in Episode VII. He provided a fairly categorical 'no.' Check out the full 'Yes/No' interview section below:
The prequel trilogy revealed that Jedi take their Force powers from intelligent microscopic life forms that live symbiotically within all living things. Therefore, Jedi and Siths are essentially individuals with an extremely high 'Midi-chlorian' count. You can watch one particularly galling Phantom Menace scene referring to them below:
J.J. Abrams has previously hinted that Star Wars: Episode VII - The Force Awakens will draw more inspiration from the original trilogy than the more recent prequels. This makes sense, since Episode VII is of course a direct sequel to the original trilogy, however, there might also be a canonical reason why midi-chlorians are not mentioned in his movie.
The rise of the Empire meant that research and testing for Force-sensitive children was banned. This meant widespread knowledge of midi-chlorians was slowly lost over time (and was presumably lost even further with the deaths of Yoda and Obi-Wan). It was rediscovered with the creation of the New Jedi Order after the events of Return of the Jedi, but it is not clear if Abrams' addition to the franchise will follow this extended universe storyline. Since being taken over by Disney, the extended universe books have been declared non-canonical.
There's still no confirmed word on whether Jar Jar Binks will be coming back though.