BBFC's rating of Mass Effect revealed that the game "contains moderate violence and one moderate sex scene", enough to warrant it a rating of 12 in spite of the fact that - according to player's choices - this sex scene might include two females.
The British Board of Film Classification report goes as follows:
"MASS EFFECT is a role playing game and shooter set in the future in space. The player controls either a male or female American soldier through a long and involved story line, making choices along the way. The game has been classified at '12' for moderate violence and one sex scene.
The violence is undetailed and takes place in a futuristic setting. The single sex scene is brief and undetailed, although there is breast nudity in one version of the scene. The sex scene is triggered by the player making a series of choices about becoming more than friends with a colleague. If playing as a male character the scene can take place between him and a human woman or a humanoid female alien. If playing as a female character the scene can take place between her and a male human or a female humanoid alien.
The game also contains use of the word 'bastard' and at least one aggressive use of the word 'bitch'. Both of which are acceptable under BBFC Guidelines at '12'."
