This isn't a bad series. It is a kind of normal sort of demonstration of how fighting in an unending war affects different kinds of people. Although the shoujo-ai aspect of it is very heavy, that actually serves to accent the philosophical arguments rather than to override them. As MrNiceguy indicates, everyone in this world is born female. For that reason, gender isn't a big deal in relationships. Choosing gender is the end of childhood, the beginning of adulthood. There is something very clever in this point which you will see as the plot progresses.