It is not clear at this time what balance in the Force meant. For all we know, the Jedi were overweight and needed to spend some hours on the space-treadmill. But on a more serious note, the movies let me believe that the Prophecy was misunderstood by the Jedi. If it referred strictly to numbers, then the balance meant decimation of the Order until there were just as many Jedi left as Sith, namely two. Anakin killed every single one of them and the only ones remaining were Palpatine and Vader vs. Obi-Wan and Yoda. So it is possible that the prophecy was fulfilled at the end of Episode 3. Luke's (and Leia's) birth would only disturb that balance once again. With Vader and Sidious out of the picture, the balance would either remain...unbalanced OR 1-2 Sith would rise from the ashes to balance things out. Another way I look at the balance in the Force thing is that some pact between the Dark and Light Sides would have to be "signed", so that the good-evil polarization is no more. Once it's gone, balance would exist, as all Jedi and Sith have taken the neutral-gray path. For this to happen, there has to be some kind of diplomacy between the two sides OR some kind of cataclysmic event that would leave them no choice but to accept to coexist. The third way I see the Prophecy is by the extermination of all Force-sensitive creatures in the Galaxy. That, or every Jedi and Sith sever their link to the Force permanently. In this scenario, either "the Chosen One" would have to go around the Galaxy killing every Force-sensitive, then committing suicide OR someone else does it (highly unlikely) OR an event severs their link to the Force. In case of the first theory on this list, the Prophecy sounds more like it was made by a Sith Lord and the Jedi were tricked into believing it, unknowingly fulfilling the plans of the original creator of the Prophecy. Now it's time for a little babbling on this subject: who is that Sith Lord? Well, I am not going to dig into the EU for an answer (I will restrict myself to the movies and my speculation). So if I am going to link this to the Darth Plagueis stuff I've posted about on the other forums (you know, the fact that he faked his death and is still alive bla bla bla), I would say that it was him who made this Prophecy. All part of his master plan - creating the Chosen One, to get rid of all his enemies (both Sith and Jedi) so that he can march unopposed to the throne of the Galaxy. So Anakin is created from manipulation of the Force, the Jedi are led into a false sense of security, train him, then ultimately get killed. And "the Chosen One" then kills his former apprentice and all is good. I know, I know, once more I may by digging too deep into this, but that's why I called it babbling.