From my understanding of Gender... (Speaking as a Cisgender Man)
Not all biologically born Men display masculine traits, nor feel masculine. Not all biologically born women feel feminine or look and act feminine. Some people are born with non-typical sexual organs either.
Gender is something society perpetuates, and because there are stereotypical traits associated at the feminine end or the masculine end of the Gender Spectrum - where people feel they fall on that spectrum, will play a big part in what Gender they associate to themselves.
Non-Binary is usually someone who feel like they do not fit one side or the other - and there are other terms people will use, such as Androgynous.
People who feel a need to Transition from their "biological" or "assigned" gender - to the one they feel reflects their personality, soul, desires etc - can be very overwhelming due to a dysphoria that affects their lives so profoundly. More and more people are feeling more confident to take that brave step, and correct society and what it forces upon them, so seeing others be respected, and acknowledge, can save them from mental anguish, and even suicidal thoughts.
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Now on to Sexual Orientation (Speaking as a Demisexual Gay Man)
Sexual Orientation is not just about whether you are attracted to masculine or feminine appearance and personalities - there is also what degree of sexual attraction you have to any gender - and what circumstances allow sexual or romantic attraction to form.
Not everyone experiences an attraction to people, either by looking at their appearance, or their personality. These would fit the Asexual spectrum. You can be romantically interested in a gender or multiple genders, but have no interest in sex at all.
I myself, am Demisexual, which means I do not experience physical attraction to anyone without an emotional connection. So I have a boyfriend and only feel sexual desire when with them.
It is also common to find "Straight" men who are attracted to, or have a sexual desire for Trans Women. Because of the appeal of femininity or their outward appearance. And what is between their legs is less important.
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All of this nuance and complication and we are only talking about humans here. Who is to say other societies, other planets, and other races - don't have their own societal constructs, and biological realities.
To anyone who is not Cisgendered, Allosexual, or Heterosexual - please correct me if my understanding is in error - I feel very self conscious speaking about things I have not experienced myself, and I want to be an ally to as many people as I can