User blog comment:Godisme/Balancer's Justice/@comment-44061-20120516171417/@comment-28861328-20120516172329

There are a few factors, however, that have not been explained in full that could either verify or deal away with your assumption.


 * 1) The Quincy are Humans. That is their definition. Humans with spiritual powers.
 * 2) "Blut" has not been explained, and while I'm not ready to jump on the bandwagon that its some Hierro-like technique, it certainly deals with the defenses of a Quincy. It was already at a certain level, which might explain why Kirge was able to shrug that damage off. Keep in mind Uryuu had many of his vital organs destroyed by Mauri-taicho, and he survived long enough to be healed - something no normal human could do.
 * 3) We know spiritual powers prolong a beings life. Ginjo has been around for quite sometime it would seem, as even Urahara and Isshin knew of him and he doesn't appear to have aged at all since he met Tsukishima as a child. Humans may be able to live for centuries with significant enough reiatsu.
 * 4) The new Quincy final form is different. We don't know how yet, but Kirge claims Letzt Stil is a "relic of the past". You can't assume that the same drawbacks that apply to the old Letzt Stil will apply to the new one.

Lastly, his wings didn't fly off. He was burried in the sand so it only looked like they were off his body. It is still too soon to assume anything about what these Quincy are or where they came from, but I think it is safe to assume that they are still Human based on the precedent already set by the manga.

I do agree, however, with you on the fact that these Quincy are very unnatural. But then again, we only have Uryu to go by, so who can say for sure?