Glossary

These are all important words to know, which I will be using to describe the books.

• Asexual – not sexually attracted to anybody.
• Agender – does not identify as any gender
• bisexual – attracted to two sexes (usually the main sexes, male and female)
• demisexual – often considered a subset of asexual; essentially an inversion of "normal" sexuality in which one gets to know a person before becoming attracted to them.
• Lesbian – female identifying person who is attracted to females
• Gay – attracted to the same sex as yourself. Commonly used for gay males, as opposed to lesbian.
• queer – generate catchphrase word covering the entire spectrum of nonheterosexual, cisgendered identities. It used to be used as an insult and can still be considered offensive by some people, but is increasingly being used as handy short summary word.
• Cisgendered – your gender identity and your physical sex match. 
• Transgendered – your gender identity and your physical sex do not match (i.e. you are a woman born into a male body or vice versa).
• transsexual – have actually physically changed your sexual characteristics (i.e. transitioning). Doesn't usually apply in most young adult fiction, as the characters are not usually old enough for the medical procedures involved.
• Cross dressing or transvestism – dressing up in the opposite genders clothing. Often unrelated to gender identity or sexuality.
• Pansexual – potentially attracted to "all" genders, including all the complicated ones in between.
• Intersex – born with physical characteristics of both sexes. 
• questioning and genderqueer – falls into one or more of the above, or still figuring some other possibilities out, but isn't sure which terms to use or if they even apply.
• polygamy – nothing to do with gender identity or sexual orientation, having multiple sexual/romantic partners at the same time(with full and open consent from all parties)
• aromantic and biromantic - subsets of asexuality, indicating that a person may not feel sexual desire, but still feels romantic interest towards one or both sexes.

It is important to note that these words do change over time, and some have become increasingly outdated, while others become more important as people become aware that there are significant numbers of people who actually fall into these categories.

Acronyms

Acronyms are a shorthand for all the possibilities above. "Queer" spectrum used to be easily summed up with "LGB", but over time, as more and more identities have been recognised as valid and mainstream, that basic acronym has become much longer. Commoner versions nowadays are LGBT and LGBTQ .

If we're trying to include everyone, it may look like LGBTQIA (adding on Intersex and Asexual). The order changes as well; it often starts out with GL instead.

But that's getting long and confusing! People have started coming up with other words and acronyms.

• GLBTQIA - Gay, Lesbian, Bisexual, Trans*, Questioning, Intersex, Asexual
• QUILTBAG - includes all the same letters, plus U for Undecided, and actually makes a word.
• LGBTTQQIIAA - Lesbian, Gay, Bisexual, Transgender, Transexual, Queer, Questioning, Intersex, Intergender, Asexual, & Allies (...this never really gets used!)
• GSM  - Gender & Sexual Minorities, a blanket term to cover everyone (becoming increasingly popular)

MtF and FtM
These Trans-related acronyms stand for the direction of their transitioning. An easy way to think of it is that the first letter, the one that starts, matches the physical sex a trans person starts with, and the other letter is the one they actual are, or will physically end up as.

• MtF  = Male to Female  (E.g. "they started out with a male body, but [it] became female (to match their gender)"
• FtM = Female to Male