They/Them/Their
Ze/Zie/Hir
The above are gender-neutral pronouns... What does that mean? Well, if you are a man or woman, you probably use he/she, him/her and his/hers. Some people are gender non-conforming- they prefer you not identify them as a man or woman. Another word people use is genderqueer, meaning they identify with neither gender, or both. Many people out there think of gender as a spectrum, not a binary (one or the other).
Gender is defined as something we identify culturally or socially, not biologically. After all, you can't tell whether someone has a penis or vagina just by looking at them, so you are using other social cues like dress, hair, make-up, etc to place them in a category. Gender non-conformists would rather you not place them in one of those categories. Not everyone who prefers gender-neutral pronouns is gender non-conforming. Some identify as a man or woman, but still use gender-neutral pronouns.
Check out this chart on pronoun usage from Desi Speaks:
You shouldn't assume to know someone's gender identity just by looking at them. You can use cues like which pronouns they use in their speech and text.
Don't know someone's gender identity or which pronouns they prefer?
Instead of trying to make a guess,