Well, if James Carville and Mary Matalin can marry, then dwarves, giants and space aliens should have no problem.
I'm not completly sure but i think i recall the mother to be half human and half klingon, which would make the child only 1/4 human ^^ As for the thread owners question; I don't see why dwarves and humans shoudn't be able to mate? There are after all way more stranger couples out there.
I'm a firm believer that whatever you can imagine happening, or whatever you can allow your mind to construct, you can write about. If it works in your story, and you can make it work and fit, why not? If you can appriciate the twist in plot or background in the history/storyline, chances are that some one else will, too.