Each society decides what it believes about gender, and about sexuality.
In many cultures like that of England, the recent tradition was that you were either male, or female. You either were straight, or gay. Possibly bisexual.
Er, that was it.
It's not it at all. Such thinking views gender and sexuality as a totally yes/no thing.
The word done by "It's Pronounced Metrosexual" is one useful guide to sexuality and gender.
It shows the five 'sliding scales' of sexual attraction, romantic attraction, gender identity and expression, and biological sex.
In other words, e.g.
a) do you feel totally female, totally male, or somewhere in between...and does that sometimes vary?
b) do you dress and act in a totally female way, a total male way, or somewhere in between...and, again, does that sometimes vary?
c) Is your body physically female, physically male, or somewhere in between? How comfortable are you with this?
d) are you attracted sexually only to men, only to women, both, neither (asexual), etc.
e) are you romantically attracted only to men, only to women, both, neither?
Each person will have a different 'sliding scale' of this.
But we don't talk about it. Arguably, we haven't even had the language to talk about it.
Who has thought about there being a different answer for sexual attraction and romantic attraction, for example?
It's worth pondering, in any discussion where people want to 'take sides'. There aren't two sides. It's more of a wibbly-wobbly wavy set of lines, curves, shapes and patterns.
Our modern understanding may never have been what more ancient cultures understood, or meant. Fascinating stuff, and wonderful.