Lordy, Lordy!
This subject matter has been meticulously avoided...
But hey- here it is in hopes of having a go.
Sephiroth says that as a boy, he was “Different from the other children.” What other children? As Shin-Ra’s most valuable asset, and the soul variable (at the time) for the Jenova project, what other children was he around? Did they drop him off at Kindercare? Or was he with other Shin-Ra staff’s children? It seems an attempt was made at socializing him, but where, and with whom is a very essential factor. Sephiroth holds some knowledge, or at least a general theory, about mommy and daddy. When asked, he answers that his mother is Jenova. However, in response to the thought of his father-- he laughs.
The problem with this, is that he doesn’t know who his father is.
Blah blah, blah- It’s Hojo. The Omega guide says this. Square said that. Okay buddy, I get it. Thing is, Sephiroth is completely unaware of who his parents are. Obviously, Jenova is not his mother, which is what he has been told his entire life. So who did they tell him was his father? This is where things get important, and basic psychology and behaviorism takes high rein. Being the parent of Sephiroth would have meant a great deal to Hojo, a source of pride and power. Even more so, as his father-- a role of control, creation, and authority. It is imperative to point out that Hojo is a psycho [killer, qu'est-ce que c'est] power-hungry egotistical man. A large majority of his psychological construction came from inadequacies, for example, being inferior to Ghast. A bit of dialog from the mad scientist himself, atop the Sister Ray-
Cloud: "Why?!"
Hojo: “Because... he is my son.”
Vincent: “..!!” [One of the most important line in the game.]
Cloud: “I like party hats.”
Hojo: “That’s right. Even Sephiroth doesn’t know. Imagine if he found out... Always looking down on me etc.”
Okay, so the party hat thing isn’t verbatim, but you should all be able to grasp the general concept. Sephiroth did not know, or even think Hojo was his father. So who was he laughing about? It wasn’t a laugh like “Dude, my dad is such a funny guy. Once he swallowed a beer can whole, and then battled Chuck Norris to the death.” It was a somber, “You don’t want to know” sort of laughter.
I’d laugh if my old man was an ex-Turk hanging out in a coffin listening to Stabbing Westward all day.
Eeehehehehe!! Uh... Wait...! WAIT! WAIT WAIT WAIT!!!
Sorry. Apologies abound. I am really stupid. Seriously. I'm a moron. (If I get knifed in the eye by a bunch of Hojo fanboys and girls, I'm taking anyone who agrees with this down with me!)
Vincent saying '...!' is so ridiculously important. Out of all the angsty, darkness that spews from his spooky lips, this is the single most important line of his entire dialog. How is '...!' important? I mean, it's some dots and a stupid exclamation point.
Think about it.
We can assume that '...!' is an expression of surprise. Vincent, is obviously caught off guard by Hojo saying this. Here is the problem with that. If Hojo WAS Lucrecia's baby daddy, Vincent would know that already. From watching the flashback, we know that Vincent is well aware of whatever relationship Lucrecia has with Hojo.
'If she is happy, then I don't mind.'
He is around during the pregnancy. Not only was he around, but as we all know, he is the one to protest the whole thing- and payed dearly for it. If Hojo was Sephiroth's father, Vincent would have known about it long before he was killed, and he would not have reacted the way he did in that scene. You also have to keep in mind that Hojo is a manipulative liar. Oh, and he's insane.
Hojo: "Because... I am his father."
Vincent: "...!"
Hojo: "That's right. Even Sephiroth doesn't know. ...Uh, Vincent...? You okay man?"
Vincent: "...?"
Hojo: "You were making a face."
Vincent: "Oh. Sorry. One of my spooky red contacts fell out."
Yeeeeah, don’t think so. I never, ever took Vincent’s ‘...!’ as a reaction of shock in response to new information. To me, it always seemed like ‘...! You really think that?!’ or ‘...! What is wrong with you?!’ When concerning Sephiroth, Vincent always exhibits deep personal responsibility, and regret. I don’t think this is due to his failure to stop the experiment- By the time he began to protest, it was already irreversible. Again, something he would have known. I think Vincent’s remorse comes from a much deeper source...
His burning loins.