Let’s get this out of the way: we cannot have a conversation about Poison without addressing her gender. Poison’s gender is part of her character and remains her most talked-about, most controversial trait. I have avoided writing a theory about Poison at all because of this, as no matter what conclusion I draw, whether I identify Poison as a cisgender or transgender woman, I will inevitably inherit backlash from all sides for merely discussing it. However, Capcom has made the never-ending argument over Poison’s biology her lasting legacy, to the point that any form of character development is practically non-existent.
For a lore theorist, it’s incredibly frustrating to write on one-dimensional characters like Poison and Hugo because, quite simply, there’s almost nothing there. There’s no story outside of a few run-ins with Cody, Guy, Lucia, and Haggar. There’s no development other than “Poison runs a pro-wrestling organization.” Unlike Ibuki, Juri, or Ryu, Poison has no bearing on the overall plot of Street Fighter. What makes this even more irritating is that Poison was around longer than any of them! A legacy character with no legacy – that’s Poison in a nutshell. Basing Poison’s entire character around her gender is like basing Guile’s entire character around being American (“I’m an American doing American things ’cause America! You don’t need character depth like a dead friend, a broken family, and a moral obligation to protect those who can’t protect themselves. Just AMERICA!!!!!”).
Even though Capcom failed to give Poison a real identity, at the very least there’s enough of a background on her to at least attempt to figure out what Capcom wants to do with her in the future, as well as see what they’ve already implemented that regular players missed. Admittedly, it isn’t a lot, but as I’ve been doing for 70-plus articles, I will give Capcom the benefit of a doubt. So, let’s take a look at one of the most controversial characters in gaming and see what her story is.
In order to find out what’s happening in the lore, we have to answer the question that looms over Poison: what is her gender? This is not an easy question to answer, as Capcom has never taken an official stance on the issue. However, there’s a reason for this: they would get negative feedback from both the fans and their own staff. They would literally be taking heat from two sides, so Capcom is wise to not say anything.
Their developers, however, aren’t taking the company’s route. According to Final Fight director Akira Nishitani, “the characters were originally planned to be cisgender women, but were changed to “newhalfs” (a Japanese slang term for trans women) after the game’s release, due to the suggestion that “hitting women was considered rude” in America and the concern that feminist groups would sue.” However, Nishitani has flip-flopped several times since, stating that Poison “could be male” but that it was up to the fans to decide, then stated that he felt that Poison is a woman, but is transgender in the United States and cisgender in Japan.
Confused yet? There’s more. Yoshinori Ono did the exact same thing after an interview where he stated: “Let’s set the record straight: In North America, Poison is officially a post-op transsexual woman. But in Japan, she simply tucks her business away to look female.” He walked back on those comments in 2011, saying that it was up for the fans to decide since “his intent was to please all fans and that the mystery behind her gender was the core of the character.” (If you’re a game developer, please don’t make the character’s gender the core of the character. You’re just gonna have a bad time.) https://en.wikipedia.org/wiki/Poison_(Final_Fight)
So, the official stance is “Poison’s gender is up to you”. However, this just isn’t good enough for either the character or the fans. What we need are answers. So, like any good theorist or good player would do, we need to go meta to find the answers we’re looking for. The thing is people have been looking at Poison the wrong way. Everyone has been arguing about what’s in her shorts when they need to be arguing about what’s in her shirt.
That’s right: Poison’s breasts are the key to figuring out her true gender.
Typically, a person transitioning from male to female will undergo breast augmentation in order to look more female. If we can determine that Poison has undergone breast augmentation, it will provide some proof into figuring out if she was born a man or a woman. So, how do we determine this?
In 2014, Men’s Health released a list of five signs to look for to determine if a woman’s breasts are fake. The Orange County Register added seven more. While both links are listed below, we’re going to rely on the Register’s criteria since they have both Men’s Health’s signs and their own.
Men’s Health: https://www.menshealth.com/sex-women/a19535101/fake-breasts/
O.C. Register: https://www.ocregister.com/2012/07/12/real-or-fake-breasts-a-dozen-ways-you-can-tell-2/
Right away, we can eliminate some of the criteria. Signs 5, 6, 7, 10, and 12 are out because these are going to be impossible to determine. We can also combine signs 3 and 11, because they talk more about the general shape of what natural and fake breasts look like.
This leaves us with six signs we can use to analyze Poison’s chest. We can determine if they’re:
1) Too close;
2) Too high;
3) Melon-shaped or teardrop-shaped;
And if:
4) There are scars;
5) Poison is skinny everywhere but her chest; and
6) Her breasts create a “shelf”.
Now all we need to do is look at Poison’s design in-game and compare. I tried to look for consistent designs across both Ultra Street Fighter IV and Street Fighter V. However, there were two things that became clear:
1) Poison’s default costumes are completely unusable for this theory. They obscure too much of her breasts to make any sort of conclusion, leaving me with non-canon costumes to judge with and leaving the possibility open that Poison is a woman only in her non-canon costumes.
2) I could find no good screenshots of Poison in Ultra Street Fighter IV that I can actually use.
So, we will be basing our conclusions solely on two Street Fighter V outfits: Poison’s swimsuit costume and the white dress she wears in her Story Mode.

Cross-referencing the fake breasts criteria with the pictures above, we discover that Poison’s breasts are, without a doubt, real. They are neither too close nor too high, they have a teardrop-shape, there are no scars or shelves, and Poison is consistently muscular around her body. In other words, if the artists were supposed to give Poison fake breasts, they didn’t get the message. There is a possibility that Poison could have used hormones to achieve natural breast growth, but as a study by The Journal of Clinical Endocrinology & Metabolism points out, any breast growth achieved would be modest. In “Breast Development in Transwomen After 1 Year of Cross-Sex Hormone Therapy: Results of a Prospective Multicenter Study”, the authors conclude, “after 1 year of CHT, breast development is modest and occurs primarily in the first 6 months.” While there were points made in the study about the measurements taken that could have skewed the results, the overarching argument is that it would be very hard, if not impossible, to achieve Poison’s breast size without augmentation. https://academic.oup.com/jcem/article/103/2/532/4642966
There is a story of a transgender woman who used hormone replacement therapy to develop a bigger bust size, but it took a course of three years to be able to reach the size she has now. https://metro.co.uk/2019/02/23/transgender-woman-thanks-nothing-but-hormone-therapy-for-her-breasts-8697627/
There’s also the biggest obstacle that Poison would have to face regarding hormone therapy: its cost. Several sources I’ve found online indicate that the price of HRT can be wildly different depending on the type of treatments used. For one male-to-female transgender woman, HRT cost upwards of $1,500 a year, or $125 a month. https://www.teenvogue.com/story/transgender-operations-hormone-therapy-costs
While that may seem cheap, costs can indeed add up over time, and for someone who would have been transitioning genders while serving as a low-level flunkie for the Mad Gear Gang, this cost may have been too much for someone in her pay grade. It’s also clear that Poison likely wasn’t helped financially by anyone in her immediate family, if the dialogue in her Story Mode is any indication.

Basically, Poison appeared to come from a poor family that lived in what she described as “a garbage dump”. Considering she likely wouldn’t have joined a notorious gang if she had a better home life, it’s pretty clear that Poison wasn’t financially sound. She just wouldn’t be able to afford the treatment she would have to take for the rest of her life.
Since we can assume that Poison was strapped for cash, and that she doesn’t appear to either stuff her bra or wear fake external breasts, we can conclude that Poison’s breast size was achieved normally.
However, even though her breasts are real and achieved without the use of hormones, there’s one more thing we need to cover: the possibility that she underwent sex reassignment surgery. The surgery itself, as seen in the Teen Vogue story above, can cost over $30,000. Poison obviously can’t afford that without robbing a bank, which is not out of her wheelhouse but would still attract negative attention for what she wanted to do (and yes, Metro City’s Police Department is corrupt, but for that amount of money, even the Mad Gear Gang couldn’t bail her out of prison).
However, what if it wasn’t a sex reassignment, but rather a sex confirmation surgery?
“Aren’t they the same thing?,” you ask. For the purposes of this theory, no. My argument is that Poison had sex confirmation surgery, but she did not completely transition from one gender to the other. With the evidence of her breasts being natural, it leads me to believe that Poison is, and always has been, intersex. While Poison has been defined several times as a “newhalf”, based on Capcom’s own designs, Poison being transgender is only part of the story.
Take a look at the two naked bodies on the following Wikipedia page. This link is NSFW, but nonetheless is important to this theory. https://en.wikipedia.org/wiki/Complete_androgen_insensitivity_syndrome
Both bodies are obviously female; however, in terms of biology, they are technically male. They are examples of complete androgen insensitivity syndrome, or CAIS, an intersex condition where a person with XY chromosomes naturally develops a female figure. The presence of the Y chromosome prevents the person from fully becoming female, however, and while the person develops breasts and a vaginal canal, internally they do not possess a uterus, cervix or Fallopian tubes. Instead, the vaginal canal ends “blindly in a pouch” and the person acquires internal testicles instead of ovaries, rendering the person completely sterile.
Because of Poison’s natural breasts, this is the most likely scenario regarding Poison’s gender. She was born with XY chromosomes, technically making her male, but her body ended up becoming female.
Where does the sex confirmation surgery come in? If Poison does have a form of androgen insensitivity syndrome, then it’s also likely she was born with some form of micropenis, as seen in partial androgen insensitivity syndrome, or PAIS (again, the link is NSFW). https://en.wikipedia.org/wiki/Partial_androgen_insensitivity_syndrome
Poison having sex confirmation surgery would serve as a way to remove “vestigial” parts and have her be able to live her life fully as a woman. In other words, she would have been born with both male and female genitalia, and had to undergo surgery to fully become the gender she wanted to be.
All of this said, there is still yet another possibility. While people have been arguing about what’s in Poison’s shorts, they could end up finding out that there’s nothing there at all.
Müllerian agenesis, also known as Mayer–Rokitansky–Küster–Hauser syndrome or MRKH, is “characterized by a failure of the Müllerian duct to develop, resulting in a missing uterus and variable degrees of vaginal hypoplasia of its upper portion.” Basically, a woman is born without a uterus, and in some instances, without a vagina (once again, the link is NSFW). https://en.wikipedia.org/wiki/M%C3%BCllerian_agenesis
There are several recorded cases you can find on YouTube or with a simple Google search, but it’s clear that this is indeed a possibility in Poison’s case. If Poison had sex confirmation surgery, the idea of having a surgically-created vagina to fix a biological anomaly would fit under that banner.
So the question remains – what’s the most likely case? Is there anything else that can point us into the right direction? There is one final piece of evidence to consider: that Roxy, Poison’s counterpart, dislikes the idea of Poison cross-dressing. Now, it could be that Poison is a woman who likes to wear men’s clothes. The only problem with this is that Poison has never been seen wearing men’s clothes. Since Roxy most likely considers Poison a man, this tells me that Roxy must have either seen Poison nude at some point or was told by Poison herself that she had a penis.
The evidence that’s there leaves me to conclude that Poison is intersex, with a condition ranging somewhere between complete and partial androgen insensitivity syndrome. In other words, she was born with both male and female parts and later removed the male parts to feel more whole. This would make Poison an intersex AND transgender woman at the exact same time. It must also be said that, although exact figures were not found, the cost of just a penectomy would be considerably less than a full transition, especially if Poison’s original phallus did not function correctly; the surgery would be more cosmetic.
So, with this out of the way, there is one more thing that needs to be discussed: the way Poison promotes herself. Typically (although not always), a person who transitions from one gender to another wants to be referred to by the pronouns that are used by that gender. Poison is addressed as a woman, even called “Miss” at one point. That being said, Poison doesn’t seem to mind too much about being seen as a man. In fact, she relishes in it.
In an Ultra Street Fighter IV win quote, Poison tells Dee Jay, “You’ve got a flashy style, but music isn’t really my bag.” Flash-forward to Poison’s USFIV ending, where she gets the likes of Ryu, Ken, Cody, Guy, Rolento, and Hugo to get together and create a rock band. Magazines around the world report on the band, with one Rolling Stone-knockoff magazine reporting on Poison herself with the caption “#1 King or Queen?”

This reveals more about Poison than her gender ever could – she’s a glory hound. The reason she started it in the first place?

She states that it’s about the band, but really, it’s about her. She wants to be accepted not just for the work she’s done but for who she is. As she tells Lucia in Street Fighter V:


This is what it all comes down to: control. This is her way of establishing control in her life, whether she’s promoting wrestlers or stealing ideas from respected Jamaican musicians. She wants the world in the palm of her hand and force it to accept her and both who and what she is.
She’s no dictator, but she did everything she could to claw her way to the top. There’s no way to box her in now.