I think you have lost the point now. The last person to revieve the Project G cells were Lucrecia. The only other's were Genesis and Angeal. So no one else would be prone to degradation. (Exceptions of the kidnapped soldiers and lazard and that scientist who my mind refuses to recall who were injected afterwards). Although Genesis and Angeal as Soldiers were showered in mako, Lazard and that scientis who were Shin Ra executives were not, so I don't think that helps.
The bottom line is everyone decayed except for Lucrecia.
It is entirely possible because she was encased in mako crystals, that she was some how protected, but then again that wont stunt any effects, she lives so long was because the jenova cells did not let her die by conventional means such as common illnesses. So it wasn't like she was frozen or anything, just left into solitude because of guilt.

Either way 2 up for Canada

Sorry for double post but I don't know if anyone knows the reason for this or can come up with a reason for this. Is this just something that was a mistake on SE's part, or is their a legitimate reason for Lucrecia not Degrading.

Yeah I thought that too, it was Project S right?

Ok sorry.. When i said she was injected with project G cells i meant she was injected with jenova cells.. i posted that so long ago i cant remember if i had a specific reason why i worded it that way instead of directly.. or if i just made a typo.. either way your absolutely right..

Now to clear up something Project G is injecting GILLIAN not Genesis directly with the Jenova cells while she was pregnant with angeal and then injecting genesis with the mutated cells Gillian created.. so this little overlook on my part cost me confusion..

Because as we see in CC Gillian does not suffer from degradation, she being the host makes her a properly mutated subject unlike that of Genesis who was injected in the womb of an entirely different mother..The details of what went wrong are still a mystery to me and i hope someone clears that up for me because im sure its just another overlooked instance. Their is the possibility that the cells were some how rejected or improperly implemented into his system causing DNA complications leading to degredation due to receiving the cells improperly (through Gillian instead of his own mother).. but if you notice in the game Angeal's degradation is not as severe as Genesis'.. you only see the visual signs just before you kill him whereas with Genesis you notice quite early on.. the difference in Angeals case could maybe be that he is in the womb of the injected host.. maybe making the cell implementation a little more cleaner and efficient but once again i don't know everything about these experiments so the reason he is a failure is lost to me..
but most importantly the host of the projects (Lucrecia & Gillian) do not suffer from degradation simply because unlike all the other sufferers they received their cells directly from Jenova.. unlike from Genesis and Angeal the flawed subjects..

Thank you very much The Sephiroth Gene.. Please read the post above yours if you haven't already. I would like to point out that Angeal indeed degraded and wasn't successful either.

I would also like to point out that the question of the topic was why Lucrecia didn't degrade even though her body was injected with J-Cells. The reason why this perplexed me so much was because I wrongfully believed that Genesis and Angeal was treated the same way as Lucrecia as in they both were directly injected with J-Cells and that the only reason why Sephiroth was a success was because he was born with the cells developing in his body just like the other natural cells due to being in the womb of a injectee. However I was way off as we all know.

So then after time away I remembered that Genesis wasn't injected directly with Jenova cells but rather the J-mutated cells from Gillian. So when I quickly seen that Gillian who was treated similarly to Lucrecia did not Degrade it only made sense that Lucrecia wouldn't degrade either. So it's no longer a mystery to me.. Thank you very much all..

I would like to bring up an argument though regarding exposure to the J-Cells. You mention that the difference between the degrees of success between Genesis and Angeal were due to the fact that Genesis was INJECTED with mutated cells whereas Angeal was merely exposed. I disagree about this triviality because the ability for cells to manipulated and replicate at immeasurable speeds. If Cells were injected into Gillian there is a high chance those cells exposed themselves to Angeal. However what I believe to be an error in thinking is that this Exposure is subtle by any means. Jenova has always been considered a virus to Gaia, and her Legacy Plagued the lifestream (Geostigma) so therefore her viral-like cells would act significantly different in regards to its replication, manipulation speed and behavior. So I believe that if Angeal was in any way exposed to the J-Cells, the implications would be potent.

The significance behind this besides the belief that Angeal was still unstable due to suitable improper implication of Alien cells, would be that Lucrecia although being injected in her womb was exposed of the cells indirectly or you can also say directly.

Im not entirely sure on this because i know close to nothing about birthing, but If your injected inside of your womb which is in your body, wouldn't that be almost the same as injecting your body I feel like it would despite my ignorance simply because alot of things from lucrecia's own body or any other pregnant female, would be connected to her unborn child (Like when she eats, she's feeding sephy). So there is a close link therefore a path for the J-Cells into her own.

I know im nit-picking right now, but i have to remain objective, and voice my ideas. Lucrecia WAS exposed to J-cells.

EDIT: According to that wikia you were reffering to, Jenova cells were indeed injected into sephy directly in his mothers womb. However i still think the physical connection between mother and child exposed her to the cells.