Idea for a story: A guy enters into a state where every time he falls asleep, he wakes up in an alternate reality, like in Ted Dekker's Circle Trilogy (cycle?). However, in mine, one of the universes is where he ends up in the army, fighting in some war (real or fictional, it could work for either), and in the other, he is feminized. At first, the two universes are quite similar, but eventually they separate out, and he has to deal with the realities of each.
I'm thinking that there are three possible endings to the story: good-male, good-female, and Bad.
Good-male is where our protagonist gets some sort of blow to the head, say, a grenade lands nearby and he escapes the shrapnel but not the concussion, or a tree branch is dislodged by shell fire and hits him. Either way, the hit jiggers his brain-circuits and he stays firmly rooted in that reality, the months of strange dreams a curious memory from the war.
Good-female is where he completes his feminization, and, perhaps, falls in love with his endocrinologist or another doctor, and they get married, and is provided with a medicine to stop his dreams for the rest of his life.
The Bad end is where he is sent into combat in one world, and becomes a sex slave in the other. As the story moves on, in the War universe, the unit's situation becomes more and more dire, and there is intense fighting. In the Femme universe, he is subjected to torment, bondage and humiliation. The two worlds end together--in the War universe, he is killed in a muddy trench, on a distant battlefield, cold and alone. In the Femme universe, his mind is broken, and he becomes a mindless cock-hungry fucktoy.