system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The difference between cisgender, transgender, and intersex

I have to present a speech in about an hour, and I am doing it on the difference between sex and gender. My presentation, after reviewing it for the millionth time, is kind of wordy and my classmates don't seem to be the brightest bunch. I was wondering if anyone could come up with a better explanation of the differences. Thank you!!
gpt
Cisgender is what most people are. Their physical sex, and gender identity are mostly in sync, so they feel 'normal' with themselves for the most part.

Transgender -as can be assumed by the prefix 'trans' being the opposite of the prefix 'cis', is the exact opposite. Their physical sex does not match how their gender identity, so they feel like they're in the wrong body. This is a depressing, often dysphoric situation for most transgender folks, and modern society's view on transgenderism as a mental illness comes with a lot of stigma. 

Then, there are things like genderfluidity, being genderqueer, and being agendered. Things things, as their names suggest; someone whose mental gender identity has a tendency to shift between one and the other; someone whose gender identity does not conform with either male or female, and don't really have a specific category; and someone who don't identify with any gender whatsoever.

Being intersex is a completely different issue to being transgender... sort of.
A person is intersex when their visible, physical sex is not one of the two 'typical' sexes. This is the case in individuals born with atypical genitalia, hermaphroditic(both sexes) genital expression, or in some human chimeras (individuals who are the result of a merging of twin embryos very early on in development).

All of these things are separate from sexual orientation, and should not be treated as one and the same.