"It's they, not her!" a friend snapped, and I was overcome with shame. Why? I had just misgendered someone by referring to them in accordance with their birth sex, rather than the gender they identity with. What gender is this, you ask? For some, it is no gender as we know it at all, and the person in question was a case in point.
For a long time, we've been led to believe that we all fit neatly into the male and female boxes that official forms, for one, offer when the gender question arises. But many people, who have since forever been invisible to most, identify with a third gender - they are queer. Not queer as in "gay" but as in "different".
The pronouns "he" and "she" do not work for these individuals, and more and more, people are demanding that society respect and accept them for who they are.
Gender queerness is not to be confused with sexual identity, as artist and photojournalist Dean Hutton, 40, points out. "It has nothing to do with who you're fucking," they - by that I mean Hutton - once told me in an interview I did for Superbalist.com's The Way of Us blog.
Gender Spectrum, a US non-profit that provides education around the concepts of gender and expression, agrees, stating: "Biological sex and gender are different; gender is not inherently nor solely connected to one's physical anatomy."
Hutton adds: "Bodies are completely different. So, people are on a different scale of how we define male or female. If you talk about intersexed people, for example, nothing says just because you are born with a vagina, you are automatically female. They open your legs and they see your thing, and based on whatever criteria they decide then that you are female or male."
Having always been particularly masculine in their expression, Hutton says they never particularly felt like a girl. "I was forced to assume that identity, particularly when I went through puberty, because my body became so feminised."
Shyam-Michael Sheikh, 20, a Joburg student who identifies as neither a man nor woman, says they fit "somewhere else on the spectrum", adding that gender is "a construct of a patriarchal society".
"She-her, he-him, these are the pronouns we are taught in the English language," Sheikh says. "However, as society evolves so does language, pronouns 'xe', 'xer' are often used as gender-neutral.
The introduction of the title 'Mx' Instead of the binary Mr, Ms and Mrs, is a sign of our language expanding out of the gender binary."
Indeed, earlier this year, the American Dialect Society recognised "they" as the 2015 word of the year. It notes that the term is "emerging as a pronoun to refer to a known person, often as a conscious choice by a person rejecting the traditional gender binary of he and she".
I feel sexuality is fluid, but if we absolutely have to put a label on it, we could associate it with the terms pansexuality or omnisexuality
Publications like The Economist and The Washington Post have reportedly adopted the use of "they" in their style guides. The University of Vermont in the US last year became the first in the world to recognise a "third gender".
No such luck at the University of Cape Town, for example, where Hutton is currently studying at the Michaelis School of Arts.
"I had to use Miss," they say of the honorific that had to go on the official registration form and, subsequently, their student card. "I asked for Mx, but they don't offer that option on their drop-down. I've never filled in a form that gave me that opportunity to choose."
Like most of us, Sheikh was already gendered before their mother even gave birth. "Throughout my womb-stay, doctors told my mother I would be born 'a girl'. Alas, I was born male."
Daily, gender-queer people are misgendered by a society that finds it difficult to fathom the complexities of gender identity.
"I recall once feeling embarrassed because a vendor gave me a bouquet of flowers because he thought I was 'a very pretty little girl'. I felt embarrassed because that wasn't who I am. I am and have always been androgynous, existing as male, female, neuter and something else all at once."
So who would a gender-queer person date? Sheikh offers: "I date whoever I feel compatible with. Gender does not play any role in my dating decisions. I will not actively seek out a person of a specific gender, but rather spend my time with someone whose mind, soul, and style arouses me.
I feel sexuality is fluid, but if we absolutely have to put a label on it, we could associate it with the terms pansexuality or omnisexuality."
As the British novelist and commentator Celia Walden wrote in The Telegraph recently: "The idea that there are two genders is as outdated as the idea that the world is flat."
Accepting this is not a matter of choice. What right do those of us have, who don't know what it is like to feel that our bodies are not compatible with our genders, to decide for others that they are male or female?
Because of how we've been socialised, it will take some major unlearning for most of us to avoid referring to gender-queer people as "him" or "her". If you aren't already doing so, now is the time to start getting to know "they"...