Representation should be a big deal, especially in gaming which is predominatly white/male/heterosexual/cisgendered.
I would imagine you could allow for transgender/LGBT roleplay by giving a few variations on the same dialogue based on not just a persons sex, but their gender and how they want people to respond to them, i.e.
1) Biologically male, male gendered, responded to as a male.
2) Biologically female, female gendered, responded to as a female.
3) Biologically male, androgynous gendered, responded to as either or ambiguously.
4) Biologically female, androgynous gendered, responded to as either or ambiguously.
5) Biologically female, male gendered, responded to as a male.
6) Biologically male, female gendered, responded to as a female.
I'm not sure sexual preference needs to be an identifier, afterall it isn't in real life. When you walk into a room do you know who is gay/straight/bi and would you want everyone to treat you such a way without ever having actually spoken to you before?