Look, to bring genetic, or science of any kind for Star Wars, it's not very good idea. Remember the fact that he actually hear esplosions in space.
BUT, if you want to think this way, well, let's imagine that force genes are recessive, what is quite natural since there are few people being force sensitive. In that case, since anakin was concieve by the force and shmi 2 things could have happen, or he got 2 recessive and very powerful genes from the force or he got 1 from the force and another recessive gene from his mother, and so, his strongest force gene may have manifest himself. So, Luke could have recieved the all powerful gene from anakin, plus another recessive one from Leia and since anakin's gene manifested himself, he was as powerful as him.
Yet, if Anakin got his 2 force genes from the force, and if both manifest themselves, Luke would be weaker then Anakin, yet the problem with this theory is that this way Anakin wouldn't have theorically a mother. So, i think the second theory is the best.
So, if we use this theory, notice that Leia, since is much weaker then Luke in the force, probably recieved the other gene from anakin, the one who came from his mother, plus the same gene luke got from Padme (because padme is non force sensitive, thus the other one has to be the dominant non force sensitive one). And, with this theory, or Han had a strong recessive force gene or Jacen would never have the power from Anakin or Luke. Yet, Ben can still have it.
Yes, but the Force doesn't work biologically, otherwise someone who had 2 non-force sensative parents couldn't be a powerful Jedi.
Wrong, because recessive genes can be present and not manifest themselves. Besides, there are the possibility of mutations that could turn non force sensitive genes in force sensitive genes.