I was browsing though the Final Fantasy wiki and ran across something in the Cetra article I hadn't heard before.

Has anybody actually heard where this idea came from? It doesn't seem to make much sense to me, with Aeris not fully understanding her hertiage at points and Hojo and Gast being so amazed by the fact that they had found a Cetra somewhere.

Anyway, here's the article..
http://finalfantasy.wikia.com/wiki/Cetra

I think the idea comes from wherever this part was found out:

I can't remember if the game tells us this through Bugenhagen or Sephiroth.

If the only difference between Cetras and humans is their bond to the planet (created from their migrations), it certainly makes "Cetraness" sound like a religion/way of life rather than something genetic. I don't know much about Buddhism/Taoism/Shinto, but the Cetras sound like they were derived from one or all of those three.

That's part of what I was thinking, but if that's the case it doesn't mak sense that the Shinra, Jenova, and Sephiroth all treated the Cetra like they were another species. Nor would it explain Hojo's attempt to breed more Cetra if it was just a belief system.

That's pretty interesting. Also, the most definable trait that Cetras had was that they could talk to the planet. Perhaps Cloud has kind of gone down that road since he can see and talk to Aeris and Zack. Same would go for the children at the church as well. It's pretty obvious that nobody else could see them or they would have made a big deal about Aeris. It might have to do with mako and/or the spirit in their body.(Geostigma) I think it's worth looking into and studying.

Hojo says though, that there is a difference between Ifalna and Aerith, something that can be seen by science.

So there's something scientifically measurable about being a Cetra, and it's probably genetics, since Hojo's research lies in that area.

18%! That's pretty exact! :o

But then, Hojo's a brilliant nutcase so I'd take his research with a grain of-- well, Gast seemed to act like Cetras were a different species too...

I might have my history messed up, but perhaps it's because the human settlements were made ages ago? The Wiki says it happened a millenia ago. Over time, perhaps information got messed up, resulting in present-day humans and even Cetras (like Ifalna) viewing Cetras as a different species when they're actually the same.

Also, assuming FFVII genetics even works like our real world genetics, and Cetras are a different species, then Gast and Ifalna shouldn't have been able to reproduce.

Well, it's probably true that regular humans and Cetra are of the same species. You don't have to be some sort of beast to show genetic differences; DNA paternity tests work on the same principle.
What everyone in Shinra seems interested in about the Cetra is their special abilities, most notably talking to the Planet and finding the Promised Land, and this is something you really can't measure. So they have to find some other way of figuring out what makes a Cetra a Cetra. Hojo apparently found something, but they never tell what it is.
Then again, Planet-speaking might not be limited to the Cetra race. If it isn't that means all the professor's hard work was in vain... :( :P

:ermm: I think in the game they only said she was from the Cetra because her mother was in fact "Full Cetra but the father was the Original Human if you get what I mean....in this case you are defined as Half Cetra but in reality your just from the Cetra and have that bond with the planet just like the others did(just being able to do more than what the natural human could do), so in short I think she cant be debated as either or...

I think the Shinra just took Aeris as she was (not minding if she was half this half that)and thought if she can do this and that then she is realiable to help us find the promised land(and take over the world...dirty scoundrouls <_< ) and also help protect the planet, but yes in the game they definde her as a Full Cetra, I believe if not some characters....

Even in Cloud's eyes (and I know this is somewhat off-topic) I dont think he cared either as far as helping the planet went (just as long she was with him and there to help the others :cleris: )

If being Cetra is simply the lifestyle, then Aerith wouldn't be a Cetra. She was taken into a lab soon after birth and later raised by a 'normal' human. Yet she still had the ability to hear the planet. There is always the possibility that Shinra were mistaken, as they were about many things. The only (reliable) truth about the Cetras comes from Bugenhaggen, Ifalna and Aerith.

I bolded what were the keywords to me. The way I interpret it is that the Cetras were a race from which the human race is descended. They are not genetically different enough to be seperate species. It's just that the human descendants have lost certain genetic traits and abilities which those genes code for over time. In this case the difference rather than being something like pigmentation is more like having lost a sixth sense (the ability to talk to the Planet) and the migratory instinct that drove the original Cetras to move from land to land.

The idea of Cetras only having a different lifestyle from other humans makes too many plotholes and inconsistancies for me. Aerith does have inborn abilities and doesn't know all of her Cetra heritage, so lifestyle alone just doesn't fit as the story was presented in FFVII.