Vincent Valentine - Mysteries
Vincent's Age
First, the obvious objection: Vincent can't be really 27. When Cloud was 8 (that's 13 years ago in the game), Sephiroth was a young hero. Hojo and Lucrecia are his parents, so Vincent must be about the same age as Hojo. Sephiroth, the 'real' Sephiroth, had to be at least about 20 then; therefore, Hojo and Vincent had to be at least 40. In conclusion, Vincent must be about 55 or even 60 years old in the game. We can, however, assume that when Hojo altered him (or perhaps during his sleep) his aging process might have been stopped or slowed down, so 27 might be his physical age, while officially he's about 60.
Vincent's Claw
Does Vincent wear a metal glove over his arm, or was his arm cut off and replaced with a metal claw? The lack of any Vincent FMV and the small amount of pics ever released by Square don't give us a chance to judge with complete accuracy.
If you want my take, I'll say that it's a prosthetic claw, mostly because to me, it doesn't look much like an arm would fit in the thinnest part of the 'glove'. You might want to check out the official art by Tetsuya Nomura (opens in a new window) to see if you can agree with my judgement.
Who is Sephiroth's father?
A number of FF7 players believe that Vincent is actually Sephiroth's father, not Hojo (who claims to be it, in the end of CD 2). Their point would be that Sephiroth looks a lot more like Vincent than like Hojo (keep in mind, however, that we never get a picture of Hojo from close enough to judge).
Unfortunately, this is one of the points where Vincent's past is very vaguely explained in the game. It's not clarified whether Vincent and Lucrecia could have had a child together or not. During Vincent's background as we see it, Lucrecia rejects Vincent and has a relationship with Hojo. While there is the possibility of a previous love affair between Vincent and Lucrecia, neither character ever says there has been one (or at least a... serious one :). Lastly, Hojo was a scientist, and he performed experiments on Sephiroth; is it possible that he never performed any DNA test? Again, while there is the possibility that he never did indeed (or didn't bother to double-check with his own DNA), I think it's very likely that Hojo's statement on being Sephiroth's father is backed by some proof of this sort.
In my opinion, Hojo being Sephiroth's real father is also supported by a more 'artistic' argument... straight from Vincent's unsaid lines of dialogue. :)
Surely you agree that Vincent is not the kind of person to say everything that's on his mind. Now, consider the dialogue that takes place when you wake him up. My interpretation is that the real reason Vincent feels so guilty and punishes himself is that he believed he was Sephiroth's father, and had failed to protect his son from Hojo's experiments (note: in this case, there has to have been a love affair between Vincent and Lucrecia, which is an assumption; but let's just take it for correct for now, you'll figure out why I do so as I go on with my explanation). When Cloud wakes Vincent up, Vincent says that hearing Cloud's story has added another sin upon him. In my opinion, this can mean nothing else than: "Oh my, I am also the one who brought such a menace into the Planet" (being Sephiroth's father).
When you meet Hojo for the last time, Hojo says he's Sephiroth's father, and if you have brought Vincent with you, he says (roughly) "I was wrong. The one that should have slept was... you, Hojo!". Now, as I have said before, perhaps Hojo would overlook a DNA comparison between himself and Sephiroth, but I do not believe that he would conduct his experiments on Sephiroth with such negligence as to not notice a similarity between Sephiroth's DNA and Vincent's, since Hojo experimented on Vincent too. Thus, the way I see things is that Hojo is indeed Sephiroth's father, and Vincent realizes that in this very point of the game. His line must mean something like: "What the heck. I thought I was guilty for not protecting my son and because my son was going to destroy the world, but it turns out that it's your son after all. Then, you're the one to be punished, Hojo!".
In conclusion, I think that Hojo is Sephiroth's father, as he says in the game; while this can't be proven with a 100% accuracy from the lines of dialogue in the game, I do believe that my assumptions (including the Vincent and Lucrecia's relationship right before Hojo and Lucrecia's) fit well when you reason not on the explicit dialogue, but rather on what Vincent is thinking and not saying, and why he says certain lines that hardly make any sense at first glance; hearing a story can't be considered a sin per se, can it? Or we'd all go to hell over playing the game... ;) hence the other meaning of that line as I explained above.