User blog comment:Brandie Janine Adams/Harry's Magical Blood/@comment-24.159.180.36-20120319013625

Apparently the blood status system is supposed to be like the Nazi Aryan system. It goes by the grandparents, not the parents. So four pureblood or halfblood grandparents means pureblood. At least one but fewer than four muggle/muggleborn grandparents means half-blood. All muggle/muggleborn grandparents equals muggleborn. Muggleborn is equal to a muggle. That's how I understand it anyway.