In the video game adventures of Commander Shepard, being a gay man was neither a matter of biology nor choice.
It was a matter of programming. And the programming of Shepard's first video game, 2007's Mass Effect, made being gay impossible.
And then things changed. The programming changed. You can play Shepard as if he is a gay man in next month's Mass Effect 3.
Why? The people who make the game wouldn't say it's because they are advocates. Not quite. They have another reason.