I'll go into this a little at the end but right now you need to accept an axiom. Before we go further, you've got to get keen on this idea. If you can't, what I have to say will be moot to you. Ready?
Diverse representation of humanity in your work is a good thing.
So when I wrote Sorceress' Blood, I set a chunk of the book in China. This meant there were a number of Chinese characters. But that makes sense, right? Book set in China, got to have some Chinese walking around. Why was it set in China? Why not? China is cool. I'm Chinese history hobbyist and I wanted part of the book to be in China.
Pilgrimage is set entirely in Australia but one important member of the supporting cast is a Japanese woman. A Japanese sorceress living out in small town Australia. Why is she Japanese? Is it important for her to be Japanese? Does her being Japanese mean anything? Is it just because I'm a massive Japanophile? Is there an in plot justification for her to be Japanese? No. No there isn't. Her magic is heavily drawn from Japanese Buddhist mysticism* but she could just has easily have been an Irish woman with magic drawn from druidic tradition or a Native American shaman type figure or a Voodooist (is Voodooist the right word?) But I chose Japanese. Sue me.
Right now I'm writing a book with a bit of an ensemble cast. One protagonist is a half-Italian girl and one is a homosexual man. Is there a reason? Does this have any bearing on the plot? Would it change anything if he was straight or bi? No. I just thought it'd be good to have a homosexual character.
I just thought it'd be good to have some diversity. I want to write a world in which there's more than hetero white people walking around.
But equally important is that those characters are not defined by the things that make them diverse. The homosexual character is not defined by his sexuality, it's just part of his make up as a (fictional) person. It no more defines him than that he is male or that he is English or that he is a Sorcerer. Rather, all of that informs the person he is and the actions he takes in the story. You know, like people.
Yasu, in Pilgrimage, is a sorceress of legendary power who also happens to be Japanese. She isn't a powerful Sorceress because she is Japanese, or because she's a woman, or because she's old. All these are traits she has but you cannot reduce her to one trait. At least, I like to think so. Critics may disagree.
But the point here is that when you're writing a diverse cast of characters, it is extremely important that you avoid tokenism and fetishisation of that diversity. I think we can all agree that Will & Grace was kind of funny but also kind of awkwardly a little offensive too but it's over and we're a more enlightened culture now and we don't need to have stereotypes in our work.
If you think you might be falling on sexual, gender or racial stereotypes, stop and reset yourself. Try writing the character without any reference to their gender, sexuality, race etc. and just write them as you think they should be written to be the most interesting character possible, then go back and add those missing details in revision.
Now I'm sure some of you are thinking, asking, "Surely if I'm writing a transgender character into my story, there should be a reason for them to be transgender. Their gender identity should be part of their arc or it should have an impact on the plot or there should be an in world reason for it." This question isn't usually asked about non-white characters but it often comes up talking about LGBT characters in fiction.
And I ask you: Why? Do you ask LGBT people in the real world to justify themselves? Do you think they need permission from you in the real world to exist? No, of course you don't because that's insane. Including diverse characters doesn't need a special reason because it doesn't need to be a big deal. It doesn't need to be any kind of deal.**
So if it's not part of the plot in anyway, how do you work this sort of thing in? Again, this isn't such an issue with racial heritage. You can tell your reader this character is a black American as easy as you can tell the reader their hair colour or what shoes they're wearing. But what about gender and sexuality?
Again, the key is not to make it a big deal.** We reveal all kinds of little and inconsequential details to the reader as we develop our characters. This character's father is dead, this character likes driving muscle cars, this character did some boxing in university, this character is homosexual, this character is allergic to latex. It's not a plot twist and it doesn't need a big reveal. Work it in naturally, just make it a part of who that character is and you'll see the place and time to bring it out and show the reader.
"Okay, Carl, so you've convinced me. This is a piece of cake. I'll make my writing more diverse. I'll include more and varied women characters, I'll have a whole range of nationalities and ethnicity in my cast. I'll have some LGBT characters. Of course, I won't go overboard. One in 20 people in the real world is homosexual, so one out of every twenty characters I write will be homosexual. On average, you know."
Look, I don't want to tell you that every book needs to have a transgender character, a Mexican character, a black character, a homosexual character and also has to pass the Bechdel test. That's not my goal here at all. I don't hold myself to that standard. But just because your life experience or some statistics you found on the internet tells you that homosexual women only ever appear once in a blue moon, that doesn't mean they should be that rare in your fiction. The goal here is to show a diverse world, not an accurate to real life world.
I'm saying make an effort. Because diversity is good. The problem is a lack of variety of humans in fiction.
Because your readers want to read about people like them. Because you provide a better experience for your diverse audience if you give them people like them, characters they can better relate to. Because there's a lot of romance and erotic books about homosexual characters but not enough homosexual action heroes. Because when you include diversity in your writing, you become a better writer.
I'd like to leave you with this image that's been floating around the internet for a little while now. If you need any more convincing, just take a look here.***
*but more on the Buddhist reading of Pilgrimage another time...
**Obviously stories where racial and sexual identity is the main theme do exist but they're a different topic.
***I've focused on sexual and racial diversity here but it extends beyond that. Diverse representation can also include characters with autism, or characters suffering depression. I have by no means been exhaustive.
****If this image is yours or you know the author, please let me know so that I can give appropriate credit and kudos to them.
Note: While I have tried to refer to all people by non-offensive terms, I apologise if my politically correct language is not current. I tried my best. Correct me in the comments if you like.