I’m currently reading Transgender History by Susan Stryker, and one of the saddening things about it is how little the arguments of anti-trans people have changed – not least the tendency to accuse us of believing things we don’t believe.

This is doing the rounds on Twitter at the moment.

If a vagina doesn’t make you a woman, how come lipstick, high heels and a handbag do?

Nobody’s claiming having heels or a handbag makes you a woman. Nobody. It’s a straw man, a made-up claim designed to reinforce the idea that trans women are unserious people who are merely playing dress-up, and anti-trans activists have been using it for over 40 years now.

“Man” and “woman” are genders, not sexes, and while they generally correspond to people’s observable birth sex that is not always the case. We’re much more complex than that.

Many cultures understand this and have long classified people into not just two genders, but many; they understand that the genitals you are born with do not necessarily dictate the gender you are or the way you will live your life.

One of the reasons we conflate sex and gender is because for many people they match. But they don’t always, and it’s often gender – how closely you conform to stereotypical ideas of what men and women should look like and behave like – that is used to classify you.

I’ve written about this before, because I find it bleakly funny: when I began presenting as me full-time the change was dramatic. Literally overnight I went from being a valued member of one project team to a person whose opinions were only worthwhile when repeated by one of the men; from being someone who could read a book in a bar without interruptions to someone who couldn’t; from being respected as an expert to being dismissed as a “silly little girl”. My genitals didn’t change, but people’s perception of my gender did.

And part of that perception is based on the presence or absence of lipstick, heels and handbags. It’s not that those things make me a woman; of course they don’t, any more than sitting without makeup in a t-shirt covered in bits of fried egg makes me any less of one. It’s that they make other people less likely to be difficult.

The closer I conform to stereotypical gender presentation, the less shit I have to deal with – so while my presentation doesn’t change my gender identity, it does change how some other people treat me.

Here’s an example. The other morning I went to my own bank to pay my own money into my own bank account. I was dressed like I normally am: skinny jeans, animal print tunic, a bit of makeup and a bit of jewellery. And normally I’m greeted without incident or misgendering. But this time out I was wearing a mask that hid most of my immaculately made-up face, and when the teller heard my voice and compared it to what was on her screen – a female pronoun, a female name – she asked me: “are you sure this is your account, sir?”

Most of the time I present stereotypically female because it makes life easier: I’d rather not be treated with suspicion when I’m paying money into my own bank account.

Biological sex is what you begin with, but gender is the space in the culture that you inhabit – and the former does not necessarily dictate the latter. You can be born with a vagina and be a man; you can be born without one and be a woman; and you can be born with any configuration and be non-binary. Other cultures have known this for millennia. It’s just taken us a bit longer to catch up.