User blog comment:Brandie Janine Adams/Harry's Magical Blood/@comment-81.151.106.102-20120317092634

Because that's not the way it works, confused me for a while to, but A Pureblood has absolutely pure wizarding ancestry, no muggles or muggle orns anywhere in the line, while Half-bloods are wizards who are born to wizarding parents, but their ancestry isn't 'pure' like Harry's, although his mother was a witch, she wasn't a pure-blood witch, so Harry can't be a pure blood wizard. And of course muggle-borns are born to muggle families. Hope this helped :)