Valve says no:
Certain games, such as BioShock and inFamous, boast their ability to present moral choices to their players, but Valve's Chet Faliszek believes that there's no such thing as morality in video games:
"There's never a real moral choice you're ever making in a game, because you're never going to have to live with that choice," Faliszek told Destructoid.
"We do things in our game to get you to behave better, to make you play together, to have this interaction in a game, but I don't think those are moral choices. I don't think games allow you to make moral choices. Games allow you to be evil, to do bad things. In Grand Theft Auto, I'm going around running people over, and guess what, I'm not doing that in real life.
"So, in the context of games having moral choices, that's a weird thing to me. I don't think they have real moral choices when I think of that. They have something else, like strategic choices, choices inside their world, but to me a moral choice is something that would live outside of a game. I don't see that."
Which is a coherent argument, though if a player can be truly embedded in a game world and can relate to its characters, surely gamers can be presented with choices that have a similar weight to moral decisions in the real world, even if the consequences aren't actually real?