What makes a Muggleborn a Muggleborn?
OK, I'm not entirely stupid. I know that Muggleborns are, at least, the wizards/witches whose parents are Muggles, and I know that purebloods are those whose parents are also magical. I even know that halfbloods are wizards/witches who have one magical parent and one either Muggle or Muggleborn parent.
So...the question is, what are, for example, Harry's kids supposed to be? Harry's a half-blood and Ginny's a pureblood. Would that make Al, James and Lily three-quarter bloods?
The same thing applies if, say, Dean Thomas married a Muggleborn. If his kids were magical then what would they be? Muggleborn? Or halfblood?
This has been bothering me for quite a while, so I'd really like it if someone could give me an answer.