Little Sister ethics. What would YOU do?

In the new game Bioshock, you are presented with a nasty dilemma. In the twisted world of The Rapture things have gone quite wrong. Without going into details, one thing that has happened as that little girls were transformed by an evil scientist into something other than human. They go around collecting something from dead bodies that is called "Adam". This is a major currency in the game used to upgrade your character's abilities. In order to get this "Adam" from them, something you have to do in order to complete the game, you have two choices. You can either kill the "Little Sister" as they are called our you can "save" them so they revert back to being little girls. If you kill them you get a great deal more "Adam" than you do if you save them. What would you do? Personally, I couldn't bring myself to kill the cute little girl. The game makes it even worse because they squirm away and beg and plead not to kill them. I'm sorry but there is no way I am gonna kill a little girl even in a video game. So hopefully I can get enough "Adam" from saving them in order to finish the game.