IGN AU was able to corner Irrational's Joe McDonagh and question the senior designer about the difficult moral decisions players will have to make in BioShock.
Q: We're just playing the devil's advocate here - because that is the natural concern for that kind of encounter in the game. But it raises an issue. A Little Sister is a child, effectively - why not use an adult and avoid the taboo completely?
A: Well, emotively, it's amazingly powerful - seeing the fate of these Little Sisters. I think, fictionally, they are the purest expression of this moral decay that this society has entered - these people have so lost touch with humanity that they're prepared to completely exploit these children, essentially. And the question we're putting back on the player is what are you prepared to do to survive? Are you going to do this? Are you any better than the people you're fighting?
I think that one of the most moving scenes in the game is, when you kill a Big Daddy, the Little Sister weeps over him and mourns him. That gets you. That has an impact. A lot of game designers have talked about bringing emotion into games - and it's been one of the great, big talking points since the inception of PlayStation 2 - and we've done that with these Little Sisters.