They do. It can occur as random mutations.
But for someone as strong as Anakin who was off the charts, there was obviously more to it.
The Skywalker dynasty is special due to that fact.
It might even be why the jedi had there no marriage and children rule. Not only because of attachments but the problems a super powerful force wielder could bring if selectively bred.
Have to wait a few weeks and see how the film plays out before deciding one way or another.