Bingowings said:

Lucas opened that door himself by making Force powers hereditary in ROTJ.

Up until then I got the impression that anyone could be a Jedi if they felt a vocation for it.

If the Force ran strong in certain families you'd think the Jedi would be encouraging them to marry other Jedi and breed like rabbits, not all the forbidden love stuff from the PT.

I used to interpret that "force runs strong in my family" line more like a hereditary fate or some kind of family curse that goes on from one generation to another, as it frequently happens in fairy tales, which all in all is what Star Wars is all about: a fairy tale in space.