Well, there is only two genders, and you don't get to choose. So kind of an odd title and premise for a game.
But games often have unrealistic, made-up stories and worlds, this is obviously just another one of those.
There is way more then two genders there isn't even only two birth sex's do to intersex people! >:( (idk if this was a joke or if your genuinely being a homophobic/transphobic jerk...if it's latter I hope karma gets you)