How does it really work? Can a child --theoretically, of course-- inherit every trait from its paranormal parent? Admittedly, in any world-building, a story can be created to defy our current understanding of biology. Anything can go, and does. But if we were to keep to the rules of today, what does "Breed" mean?
Breed is certainly an important element in raising livestock. The Department of Animal Science at Oklahoma State tries to define breed in their article, "What is Breed?": "Animals that, through selection and breeding, have come to resemble one another and pass those traits uniformly to their offspring." The article continues to explore the problems in defining breed, which is in large part, opinion of the breeders.
For a male vamp to pass only vamp DNA and none of the human mother, then this could be termed "true-breeding." In the real world, this is closer to what happens within the plant kingdom. Picture a self-pollinating plant which will produce a plant with all the same characteristics. In this case, though, the vamp would be contributing all of the DNA. Nothing from the mother.
What does all of this mean? You can create a hybrid of your ordinary/paranormal couple, combining dominant and recessive genes, or you could assume your paranormal side of the equation always passes dominant genes. Thus, one vampire parent will always produce a vampire offspring. Vamps breeding true does actually have some real world biological basis. And who couldn't believe an alpha-type male would be dominant, even on the genetic level?
Now I can think about what that means to my own world building.