As a die-hard Whovian whose first (and so far only) novel-length completed work is a Doctor Who fanfiction:
People are not stereotypes, patterns are stereotypes.
How many gay/bi characters do you have who
aren't villains?
Extensive personal experience
The Whoniverse (Doctor Who, Torchwood, Sarah Jane adventures) has two characters that the writers tried to make as superficially similar as possible (one guy goes by the alias of Captain Jack Harkness, his psychotic ex-husband goes by the alias of Captain John Hart, both are bisexual/biromantic and extremely promiscuous, and both used to work for the Time Agency as law enforcement officers) so that the fundamental differences would stand out more strongly (Jack is a leader who goes back and forth between being Neutral and being Good, John is a loner who goes back and forth between being Neutral and being Evil), so when I started writing my own story, I wanted my main character to be a former Time Agent like Jack and John.
Naming her "Captain JH" wasn't too hard, I'd found a lot of names websites and settled pretty quickly on June Harper, and I've always been very prudish about sex and sexual expression, so I thought it would be helpful to me to force myself to write about somebody as promiscuous as Jack Harkness or John Hart.
I also realized about 3 chapters into writing that I wanted her to be a villain. I'd been reading about how not to write female action heroes, and one tip on what
to do is that women tend to fight dirtier than most men do, for the same reason that smaller men tend to fight dirtier than bigger ones. I came up with a scene where she snaps the neck of an antagonist to the surprise of her male friends who'd been engrossed in the antagonist's monologue, and I realized that I could turn this into a much larger statement about vigilantes in general.
I've always loved the concept of the villain protagonist (I loved KA Applegate's
Visser and Shakespeare's
MacBeth as a kid), and in my adolescence I'd fallen in love with the vigilante serial killer concept (Dexter Morgan, Light Yagami, Walter Kovacs). But I've always hated when they were treated as the heroes.
When I realized that June Harper worked best as being more ruthless than the rest of my characters, I realized that I could take this a few steps further and turn her into a bloodthirsty vigilante serial killer that her own friends are afraid of (though not on their own behalf) to show that "Yes, these people murder the bad guys, but that doesn't make them the good guys." I'd also fallen in love with the Token Evil Teammate dynamic whereby one Villain Protagonist and a number of Hero Protagonists work together against a Villain Antagonist (Belkar Bitterleaf from
Order of the Stick, Spike from a few seasons of
Buffy the Vampire Slayer, arguably Jayne Cobb from
Firefly), and I wanted to see how that dynamic changes when the villain is the one
in charge of the Protagonists rather than one of the heroes.
This also made the symmetry more beautiful: Jack Harkness was a heroic leader, John Hart was a villainous loner, and now I was finding out that June Harper worked better as a villainous leader than she had when I was writing her as a heroic leader.
Then I read an article about Orson Scott Card and decided that I should probably look into LGBT stereotypes.
I'd assumed that my being asexual/aromantic would make me less likely to do something wrong than a straight person would, but after reading about how Card had gone from being so tolerant of Islam to being so bigoted against LGBT, suddenly I felt I should double check.
Turned out that "gays/bis are promiscuous" and "gays/bis are evil" were nasty stereotypes even on their own, let alone combined in the same character. I tried to change my characterization of June Harper, but nothing felt real to me because she couldn't be anything in my mind
except a promiscuous, bisexual serial killer.
And then I had one of the most important brainstorms of my life: the problem wasn't that my bisexual character was a promiscuous serial killer, the problem was that my only bisexual character was a promiscuous serial killer.
I immediately went to the rest of my cast to see which of them could be made bisexual/monogamous and which ones could be made promiscuous/straight. I managed to work two of my guys (one of whom I'd been convinced was aro/ace like me) into being a couple*, but I couldn't in good conscience make any of my other cast promiscuous.
This actually made his character as much better as it made hers. One of his first lines was complaining about how promiscuous she was, which I'd originally intended to be an asexual complaining because all of you look like that to me on my bad days, but then realized that without him being expressly stated as being ace, he would be assumed to be straight and be complaining about how bisexuals are more promiscuous than straights.
Finding out that he had retroactively been bi the whole time turned that line into a line about a bisexual complaining about how annoyingly different the other bisexual is from himself, and having a bisexual man and bisexual woman being platonic (in spite of her best efforts) best friends was even better than having a straight man and straight woman being platonic best friends (which, again, I don't see enough of, but I'm doing it in my new Urban Fantasy WIP)
So I came up with a new guy
I'd been toying around with the idea of a less humanoid species being a bigger part of my story anyway (so far I had 4 humans, 2 Time Lords, and a sentient ship), so I figured I would come up with a non-humanoid character and make him promiscuous and straight. I then hit my Doctor Who encyclopedias* and the wikis looking for a good non-humanoid species to use.
*Yes, yes I just said that.
BTW: there was an arc I was planning for one of my characters, and there was another arc that I was planning for a few of my others.
Completely by accident, the non-human character I came up with ended up reflecting
both arcs simultaneously, and both sets of character(s) benefit more from their exposure to his similar development