I see several issues here. In my current playthrough I am a Female Drow Ranger, building a relationship with a certain female cleric. In real life I am neither female nor drow, nor am I involved with a member of the same sex (not a ranger either, but that isn't relevant.) If I want to be gender neutral in my mind, I can be - but I recognize that from the "image" I present, my voice, hair style, mode of dress and such, I will appear to be SOMETHING. that something may very well not be what I think myself to be, but I have no control over what another character perceives.
This is a game - certain features of your character may be obvious, and under a players control in any game - name, appearance, voice and such. Certain other characteristics, sexual identification and preference among them, will NOT be obvious. They are still under your control to the extent possible. You can embark on a relationship with whichever character you want, you can THINK of yourself in any fashion you want. But you still cannot control how others perceive you.
Even in the real world, you are dealing from a situation in which humankind has considered itself to be a binary race for thousands of years - male and female (leaving aside the statistically rare exceptions born with either no sex organs or both sets of sex organs). Genetically, a person is either predominately male or female. There 's no "other". If you are born male, and wish to consider yourself female, that's fine by me - but someone just meeting you will still classify you based upon observable criterion - appearance, voice, dress, mannerisms.
In most cases, when speaking TO you, someone will generally NOT be using genderized terms - such terms are used when talking ABOUT you, not directly to you. The exception being upon introduction, when someone might for instance refer to you as "maam" at which time you might correct them. And the reality is, in the real world, the person you correct might just not give a damn. In game land, If you think an Orc is going to get into an ethical conversation with you over your binary status choice, you are likely sadly mistaken. Said Orc does not give a rats ass what you are - other than enemy or friend, or maybe dinner. Of course, Larian COULD give you the option to demand said Orc refer to you as you want, and when Mr. Orc laughs at you and starts looking up cookbook options, provide you the opportunity to scorch said Orc's ass with a flame arrow, then calmly ask Mr. Orc to reconsider, but I think that will be a stretch on their resources.