Because there aren't enough divisions under the Transgender umbrella...
I've just been exposed to the term "demiboy":
There is, of course, a matching "demigirl" term and more encompassing "demigender." Although I think a lot of terms we use are attempts by people to describe the same identity using different words, I do like the idea that "demi" captures the identification with a gender that is not strong enough to assert being that gender. So those of us born male who have decided that we're non-binary but still have a historical/habitual connection to maleness might well be described as "demiboys." Or we might feel attachment to both genders but not strong enough to identify and either and be "demifluid."A demiboy, also called demiguy, is someone whose gender identity is only partly male, regardless of their assigned gender at birth.[5] They may or may not identify as another gender[6] in addition to feeling partially a boy or man. They may also define their identity as both male and genderless (agender).
"Alternatively, demiguy can be used to describe someone assigned male at birth who feels but the barest association with that identification, though not a significant enough dissociation to create real physical discomfort or dysphoria, or someone assigned female at birth who is trans masculine but not wholly binary-identified, so that they feel more strongly associated with 'male' than 'female,' socially or physically, but not strongly enough to justify an absolute self-identification as 'man'."
http://nonbinary.org/wiki/Demigender
An interesting addition to the lexicon. I have always said we spend most of our time finding out what we're NOT. So it's one more thing to try on and see if it describes us.Demifluid is a gender identity for "someone whose gender is partially fluid (genderfluid) with the other part(s) being static; an example could be: one part of their gender is 'woman' while the part that fluctuates is 'man' and 'genderqueer'."