Explain This Passage

[Carol]

No: HPFGUIDX 180516

Allie:
> 
> I wonder what Harry and Ginny's children would be considered.  
> Harry, being "half-blood," and Ginny being "pureblood," would that 
> make them 3/4 bloods?  :)  For how many generations must one's 
> parents be magical before one is considered pureblood? 
> 
> Even most muggleborn children will marry witches/wizards (since they 
> will be surrounded by them for most of their lives), so 
> theoretically the number of "Fullbloods" will be GROWING, even if 
> the number of "Purebloods" is shrinking.
> 
> Allie
> Who likes Steve's new term
>
Carol responds:
Steve's term isn't new. He's been proposing it for years.
Unfortunately, however sensible and logical "full-blood" may be, it's
not canonical. Neither is "3/4 blood" or any similar term. Wizards,
not being, for the most part, particularly logical (as Hermione points
out when she solves Snape's logic puzzle in SS/PS), don't think in
those terms. Slughorn's reference to chromosomes to the contrary, they
don't think in terms of genes, either. It's all "blood." So people
either have Wizard blood or they don't.

So here's what we know we have, per canon:

A Muggle (no Wizarding blood)

A Squib (Wizarding blood through at least one parent but no magical
powers other than being able to communicate with cats and see Hogwarts)

A Muggle-born (a Witch or Wizard with two Muggle parents and, by
implication, four Muggle grandparents, IOW, no Wizard blood and
therefore, the same as a Muggle to pure-blood supremacists)

A Pure-blood (a Witch or Wizard with no known, or at least no
acknowledged, Muggle ancestors)

A Half-Blood (a Witch or Wizard with one Muggle or Muggle-born parent
and one Pure-blood parent)

That, of course, raises the question you raised, what to call the
child of a Pure-blood and a Half-blood, as well as the child of a
Muggle-born and a Half-blood.

I think, though I can't be sure, that Wizards in general (whether or
not they believe in pure-blood supremacy) would consider a Half-Blood
to have Wizarding blood and therefore would not count that person as a
Muggle in the bloodline. However, that person's Muggle or Muggle-born
parent would count as a Muggle grandparent, preventing the child of a
Half-Blood and a Pure-blood from being considered a Pure-Blood himself
or herself. However, if that child were to marry a pure-blood, his or
her children could count themselves as pure-bloods if they were so
inclined because they would have no Muggle )or Muggle-born) grandparents.

Case in point, Albus Severus. He has one "Muggle" grandparent, Lily
(no Wizarding blood despite her magical powers), so he counts as a
Half-Blood (not subject to the prejudice a Muggle-born might suffer,
but not "one of us" in the pure-bloods' view, either). However,
suppose that he marries a pure-blood (if any pure-blood girls are left
after JKR's purge). That child's grandparents would be Harry (a
Half-Blood but counted as a Wizard, unlike his "Muggle" mother) and
Ginny, a pure-blood, plus two unknown pure-bloods on the mother's
side. I doubt that even the Malfoys would deny that child pure-blood
status. He'd probably be regarded as restoring the Potters' pure-blood
status.

Ron's and Hermione's kids, of course, are Half-Bloods, and something
similar would occur if Rose married Scorpius Malfoy. (Who knows? Draco
might even approve such a marriage given the shortage of Half-Blood
wives available for Scorpius.) Their children would have one Muggle
grandparent, Hermione, preventing them from being pure-bloods
themselves, but if those children married pure-bloods, *their*
children (Ron's and Hermione's great-grandchildren) could,
theoretically, be counted as pure-bloods. Either that, or there won't
be any pure-bloods left because no one will qualify, in which case the
terms may fall into disuse (and no one that I know of would consider
that a bad thing).

As for the child of a Muggle-born and a Half-Blood (the children Harry
and Hermione would have had if they'd married each other, for
example), we're back to counting a Muggle-borns as "Muggles" for the
purposes of bloodlines. Those children would have had *three* Muggle
or "Muggle," in Lily's case) grandparents, and would be at best
Half-Bloods in the eyes of pure-blood supremacists (though they could
not count as Muggle-borns because of Harry's pure-blood father). 

If two Muggle-borns married, both would count as "Muggles" because
neither had any Wizard blood and their children would have four Muggle
grandparents, so, for the purposes of pure-blood genealogy, the
children would also be Muggle-borns. Probably, not even the most
prejudiced Witch or Wizard would refer to them that way to their
faces, however, since they would grow up in the WW and know what Draco
calls "our ways." They would be considered unsuitable marriage
partners for the scions of some pure-blood families but would probably
suffer no more prejudice than Half-Bloods in general.

Carol, just working out what JKR didn't specify and not sure that JKR
would agree with her answer