The Jedi are fundamentally against forming personal attatchments, but they do bear children here and there. Ki Adi Mundi for example has several children with several wives on his home planet, because there is such a low % of men compared to women and everyone has to "do their part" so to speak, or something like that. Also there is the idea that hereditary traits could skip a generation as well, resulting in a non Jedi candidate to bear a jedi candidate.
If anything, I think the Midichlorian concept serves to make the Force -less- hereditary. Before Luke was strong in the force simply because he was Anakin's son. Now it's more specifically, because he (like his father) had a strong predisposition to use the Force. Now with the Midichlorian concept, it's not that they are fundamentally different from the other beings in the galaxy, they just have an easier time tapping into the Force.