"What's your flava – tell me, what's your flava?" I am, of course, invoking the great early 21st century poet and philosopher, Craig David, to help me find out something I'm dying to know. Just what, exactly, is your gender identity? If you answered "erm, what do you mean?" or "duh, I'm a man/woman" then I'm afraid to say you've become rather passe. Ask a transgender person or a feminist this question and they will know exactly what you mean and will also have a very definite (if not always clear) answer for you.

Most people never really stop to question the identity carved out for them from birth, but for those who do, there's a smorgasbord of options to choose from. Woman. Trans woman. Trans man. Genderqueer. Androgyne. Intersex. Bigender. Gender nonconformist. The list is endless and I suspect most people will never have heard of the various nuanced terms coming their way. Does the word "cis" mean anything to you? It means anyone who isn't transgender; it is to "trans" what "straight" is to "gay". You'll probably have to get used to it. Sorry. We're trying to change the world.

Changing your gender identity has officially become a thing – Facebook says so. Following years of complaints from transgender people, the world's largest social networking site now recognises 56 gender identities in the US. The plan is to extend this worldwide, all in the name of furthering the rights of all its users.

Overall this is a progressive move and will delight a community that seldom has much to rejoice over. It will also annoy Daily Mail readers too, no doubt, and for that we should be thankful. It screams of "political correctness gone mad" and I look forward to rightwing commentators telling us how absurd it is and how affronted they are by something that really isn't a concern for anyone other than those it concerns.

But before we all break into I'd Like to Teach the World to Sing, let me play chief party pooper. I doubt Facebook did this as an act of pure progressiveness to cater for its transgender users and I can't help wondering what the commercial imperative is. What money is there to be made by sorting people into ever more specific boxes?

Advertisers will be wetting themselves – particularly anyone selling wigs, chest binders, or any of the other specialised products aimed at those of us who seek to change our gender. It's the monetisation of minorities.

But – as many of my Facebook friends have pointed out, wouldn't it be better to leave a blank box for people to dream up their own gender identities? Why choose from 56? There are as many possible gender identities as there are people, so why not let people come up with their own categories, or even better, why have a gender box at all?

We take it for granted that we are so frequently asked to declare our gender. We do it with race too, but not so much. When was the last time you filled in a form that didn't ask you about your gender? Every time we circle a Mr, Mrs or Ms, what are we really saying? In some cases it makes sense to sort people based upon their physical anatomy. People aged 25 and over with vaginas need smear tests, so it's useful for doctors to know who has one. But outside of purely medical contexts or situations where people insist on being addressed with some sort of gendered title, what's the point? Do we truly need that information on passports?

I remember when I first came across the term "trans woman". Up until then I'd assumed I was one of those transsexuals you read about in the paper. Not a woman or a man, really – something inbetween. It sounds cheesy in retrospect, but I remember feeling truly energised by my discovery. Trans woman. Like black woman. Or disabled woman. Or French woman. I realised I could still be a woman while acknowledging the transgender part of my identity. I wasn't an imposter after all, just part of the wide diversity that makes up womankind.

I suspect that the changes will make most difference to people who identify as neither male or female – "outside the gender binary" if you want to be really fancy. I doubt I'll fiddle around with my gender settings on Facebook. I've done enough of that in real life, thank you very much. If I had the option to list myself as "gutsy northern ladette", "loose woman" or "bad girl", I might change my mind, but until then I'm not fussed.