Everyone Is Bi

""You people and your quaint little categories.""

- Captain Jack Harkness, Torchwood

On many mainstream American and British TV shows, there are No Bisexuals. Not just in the casts, anywhere; once a person has realized his or her attraction to the same sex, the opposite sex is expected to be discarded utterly. A bisexual, at best, is either a kinky guest star or the one who did it.

This, needless to say, is hardly a case of Truth in Television. In the real world, many people can be attracted to either gender (or neither), and if someone's previously expressed an attraction to their opposite gender, bisexuality is generally the safer naïve assumption. Many shows seem to be moving toward that paradigm, but the base assumption in TV land is still generally that you're either/or, and Joe Average's assumption is still that "bisexual" means Anything That Moves. Curiously, this is not all that different from how homosexual characters have been treated. "Educational" films like Sid Davis's Boys Beware (1961) suggest that homosexuals are all child molesters, and even modern gay men are often portrayed as willing to sleep with any and all consenting males.

Of course, then there's the other extreme: Everyone Is Bi. Gender, aside from a few token comments, is hardly a factor in the characters' relationships; the gender barrier seems an alien concept.

What this trope is not is, for example, the webcomic Umlaut House. While about half the cast is bisexual, the other half is explicitly not - and even if the ratio were different, the fact that neither half will shut up about it makes it the antithesis of this trope, in which it's rarely, if ever, mentioned at all.

And sometimes, even when everyone is straight, the fans don't seem to think so.

If one were to turn this trope upside-down, then Everyone Is Asexual. Invert it, and you get, well, the opposite. Compare Cast Full of Gay.

Everyone Is Bi is only played straight about half the time (from statistics, it is played straight exactly 52.4339272761775434553% of the time).

Anime and Manga

 * Revolutionary Girl Utena: The TV series contains suggestive scenes and dialogue between nearly every pair of major characters, including siblings. The director kept pushing the envelope until not even the most diehard of Have I Mentioned I Am Heterosexual Today? fans could call it "just Ho Yay". Even the manga artist, initially disinterested in the plan for girl-girl intimacy, came around near the end of the series. The brakes came all the way off for the The Movie.
 * The second half of Gravitation.
 * Seems to have been the general assumption in Kyou Kara Maou, as it is 'not uncommon' for two men to marry, and the maids who have a betting pool on the main character's relationships don't even take gender into consideration despite his having explicitly stated his heterosexuality several times. Or perhaps they just know better.
 * It seems like absolutely everyone in Axis Powers Hetalia is at least bi.
 * France canonically is. Word of God, volume 1.
 * Word of God says that Sweden's gay, but only for Finland.
 * This is what happens when 90% of your cast is male, but you still want to have romance/sexual tension/etc.
 * Prussia is hinted to be in love with Hungary and is also shown to like Italy very much, only referring to him as "Italia-chan", considering him 'cute' and even going as far as to ask him on a date in the drama adaptation of his blog event, only for Italy to be oblivious to his question, having been fixated on Prussia's bird.
 * S. Italy Romano. He can be very Hot and Cold for Spain, but he is somewhat of a womanizer as well (and there was that one time he had a crush on Belgium...)
 * Austria has been married to Spain and later to Hungary.
 * Turkey is known for pursuing Japan and possibly Iceland, but in the past he also pursued Greece's mother Byzantine.
 * Fanfic often portrays bisexuality as an integral part of being a nation, since technically they don't count as normal humans.
 * Kaguyahime: Mostly everyone but not only because of Miller and Akira. Except for Maggey and Mayu, who both definitely think men are dicks.
 * In Mnemosyne, the entire issue of gender in sex is just discarded. For example, the main character Rin has shown to have sex with both males and females, with, and the rest of the cast is implied to simply go with what feels good to them. That said, however, gender is an issue to the greater storyline...
 * Gorgeous Carat: Characters' sexualities are never addressed (except for a couple 'are you gay?' jokes at Ray's expense). The guys just all want Florian.
 * Vampire Game: Exactly What It Says on the Tin, with the exceptions of Darres, Falan, Vord, and Ishtar, several of which still encourage all sorts of bizzare matchups.
 * While almost any manga by CLAMP may qualify, Cardcaptor Sakura in particular stands out, what with most of its main characters having both opposite-sex and same-sex attractions.
 * Dutch manga Penny's Diary turns this up to eleven as not only bisexuality such the norm that "uniseksuals" (a pair of classmates, the main character's straight best friend and an aunt) are seen as a harmless quirk while casual sex is encouraged between anyone from family (holidays traditionally ending in a post-dinner orgy,) teachers with students and Mall Santa (St. Peter) and Black Pete. The age of consent in the series is 4 and drawn in a chibi style.

Comic Books

 * In Strangers in Paradise, most of the female characters have slept with each other, even if they self-identify as straight. However, even if they do not like men, they have also slept with David. Love Dodecahedron does not even begin to describe it, and it is one of the only series to have the characters themselves actually suggest multi-partner pairings in order to deal with the results.
 * Wendy and Richard Pini, creators of Elf Quest, have explicitly stated on several occasions that every single elf in the series is at least potentially bisexual. Although most of the characters seem to express a preference for one sex or the other there are several examples of elves in heterosexual relationships taking time out to have same-sex flings as well, perhaps the most notorious being Leetah and Nightfall's nude dance in Volume 5 of the collected series.
 * Similar to the 51st century in Doctor Who, the eponymous superhero of Midnighter once tried to explain to a woman from the 95th century that he's gay. She didn't understand the word, and revealed that in the 95th century Everyone Is Bi (apparently that's enough of "everyone" that they no longer even have words for monosexuality).
 * In Alan Moore's League of Extraordinary Gentlemen the character of Orlando is definitely bisexual, but this makes sense because Orlando is an immortal who changes sex randomly and without warning. However, pretty much all of the female characters (be they historical or mythological) that Orlando spends any amount of time with are bi for Orlando. This includes Mina Murray, the heroine of the series, Fanny Hill, Venus (of course), Marguerite Blakeney and others. And when Orlando is a male, it's at least hinted at and also sometimes explicitly stated that many of his male companions are bi for him also.
 * In Century: 1910, Mina, angry with both Orlando (who's male at this point) and her partner Alan, announces that she'll be in self-Exile To The Couch, and they'll have the bed to themselves. She also comments that she likes Orlando better when (s)he's female.
 * In Artesia, all the Daradjan women seem to be bi, and the men at least have no problem double, triple, or even quadruple-teaming a willing woman. No male characters have yet been shown to be explicitly bi or even homosexual, though.
 * In Jaime Hernandez's "Locas" stories in Love and Rockets, practically every female character is bi, even the lesbian-identifying ones. Except for Vicki, who's a homophobe.
 * Every female in Cherry Comics.

Fanfiction

 * Everyone in the That Damned M Preg universe is bi unless specifically stated otherwise, exclusively straight and gay characters are few and far between.
 * My Immortal, though only the guys show it—for the girls, it's just an Informed Attribute. Ebony herself flip-flops between Bi the Way and Have I Mentioned I Am Heterosexual Today? for no adequately explored reason.
 * Absolutely everybody in Kim Possible fanfic, Depending on the Writer.
 * In C'hou in With Strings Attached there are no sexual taboos amongst the C'hovites; hence, Everyone Is Bi. For example, when Ma'ar asks George to sex with her, she tells him to invite the others in and they'll all enjoy one another. (Given that the four are firmly heterosexual, George agrees to sex but asks to leave the others out of it.) Grynun says that inside the castle walls, the four can have sex with each other but with none of the Idris until she has them first. And As'taris ogles the naked Paul and comments to Grunnel that if he'd known what he was missing, he wouldn't have treated Paul so indifferently.
 * This doesn't apply on the Hunter's world; he talks of the “shameful female-men.”
 * Choose two characters in all of fiction. There is a fic pairing those two. Now notice how gender was not specified in the prompt. That is because everyone can be bi in Fan Fiction.

Film

 * Bedrooms and Hallways: The premise of the film is that sexuality is not set in stone.
 * Gia
 * The Rocky Horror Picture Show.
 * Velvet Goldmine has Brian and Mandy and a host of glam rock fans.
 * The extraterrestrials of Paul, at least according to Paul. He also says "It's all about the pleasure," which might indicate he's not being completely sincere.
 * Most mainstream porn, of course, meets this trope halfway - it's true by default for women, but not for men. (There's a fairly small subgenre where it's true across the board.)

Literature

 * In Jacqueline Carey's Kushiel's Legacy and Kushiel's Scion series, every single d'Angeline character is bisexual. Absolutely without exception No exceptions.
 * In Diane Duane's The Tale of Five fantasy series, bisexuality is culturally universal in the world it takes place on.
 * To the extent that they have laws dictating that everyone must have at least enough heterosex to produce a couple of children. After that they can go back to their real loves.
 * In Piers Anthony's Apprentice Adept series, the serf class on Photon can be inferred to be mostly bisexual - mostly out of having to cater to the whims of the Citizen class (lead character Stile mentions "consensual heterosexual encounters", implying there's been homosexual ones and possibly voluntary). There are however, only two verified bi characters (Tania and Tsetse - naturally both female and hot.)
 * Note that this only became the case in the last book. Prior to that, homosexuality was barely even sidebarred.
 * In Merry Gentry, pretty much all of the Fey are supposed to be openly bisexual. Merry herself is all about the heterosex, of course, so that she can reflect the author's own feelings about sex with another woman, which seem to be "ewww gross but that's actually kind of interesting".
 * In Hamilton's other series Anita Blake: Vampire Hunter the number of minor and major male characters who aren't bisexual can probably be counted on one hand (and there are quite a few male characters) including just about every one of Anita's love interests. Interestingly it is made very clear more than once that Anita herself is not interested in women and most of the female characters that are tend to be pretty villainous.
 * In S.M. Stirling's Draka novels, the old 20th-Century genetically-unmodified-human Draka are straight, gay, or bi as the case may be (and with no shame or self-consciousness about their orientation ever); but the genetically-engineered New Race or Homo drakensis Draka, portrayed in Drakon, are all bisexual (and their sexual appetites always ravenous).
 * Anne Rice 's vampires are functionally asexual, but there's a lot of erotic subtext to their interactions nonetheless.
 * Arguable with some other characters in the series, but Lestat is absolutely bisexual; he has an intense love affair with his male best friend before becoming a vampire (nothing subtextual about it; they kiss multiple times, live and sleep together, and are strongly implied to have sex), and harbors deeply erotic thoughts about him even after the transformation. Considering the nature of his inclinations and relationships afterward, it's pretty obvious that he retains a pronounced attraction to men even after his ability or desire for physical sex is lost when he becomes a vampire.
 * In Armand's book, she finally had the main character have sex with persons of both genders before he was turned.
 * The same author's Cry To Heaven runs on this trope. The main (castrated) male character has love affairs with people of both genders, although his same-sex relationships are more numerous and generally more dwelt upon by the author. His two most lasting affairs are with another castrated man and a woman, respectively, and he thinks of both of them as the loves of his life at different points in the novel. He even carries on a sexual relationship with a cardinal in Rome, who (at first) justifies the affair with the church's belief that castration renders the person neither male nor female, and thus a loophole to rules about celibacy. It doesn't last.
 * Larry Niven's Known Space. According to one interpretation, which is in line with the way the Puppeteers themselves generally explain it to non-Puppeteers, Pierson's Puppeteers can be regarded as an entire race of bisexuals. Males are sapient and produce gametes, while females are non-sapient and provide gestation space. There are males who produce sperm and males who produce eggs, while females contribute no gametes but carry and bear the offspring. The female dies after childbirth, and the gay couple raises the kids, no sex except reproduction though. Would be Everyone Is Gay if the couple didn't have sex with a female at one point. An alternate interpretation, one that a human character stumbles upon and considers more accurate, is that the non-sapient "females" are in fact a different species that the Puppeteers are parasitic upon - similar to the Ichneumon wasps that lay their eggs in live insects so that the wasp larvae can eat the host alive. The "sperm-producing-male" is the Puppeteer male, while the "egg-producing male" is the Puppeteer female.
 * Practically everything Poppy Z. Brite has ever written.
 * An astonishing number of the female characters in the Claudine stories are bi. This is shrugged off with the ignorant contemporary views of sexuality- as Claudine's husband says, "What you little animals do is charming and doesn't mean anything." It's another matter entirely if a man should be interested in both sexes.
 * In the novels by Gregory Maguire (especially Wicked), everyone is bisexual until they state they don't care for one or both genders. (Especially if you're descended from the Thropp line.)
 * Hell, in terms of ruining your childhood, it wouldn't be much of a stretch to pin this on the Baum Oz books.
 * In Fiona Patton's Tales of the Branion Realm, pretty much everyone is bi, and this goes completely unremarked. There is even a Guild of Companions (a cross between bodyguard, courtesan, same-sex sexual partner, and spy) who are contracted to the nobility. The first book revolves around the Crown Prince's relationship with his mother—she wants him to get married and have an heir, he would prefer to shack up with his Companion. He starts a civil war over this. His mother, BTW, has four Companions of her own.
 * In Robert A. Heinlein's Time Enough for Love, Ishtar and Galahad agree to "Seven Hours of Pleasure," even though they have so far seen each other only in all-concealing biohazard-protection suits and, thus, neither knows the other's sex. It is strongly implied that in their society (the Howard Families colony-world of Secundus), it is considered in bad taste even to care.
 * Each one is pleasantly surprised to learn the sex of the other, as Ishtar is oddly tall and Galahad is oddly short. And both are absurdly beautiful, particularly Galahad (think the statue of David, except not terrified).
 * Speaking of Heinlein, it's also implied in Stranger in A Strange Land that sexual bonding in the Church of All Worlds can occur between any water brothers regardless of gender, although this is done extremely subtly by Heinlein's standards.
 * An Informed Ability in the Doctor Who Expanded Universe. In All-Consuming Fire Benny says that bisexuality is the norm in the 25th century (although she personally isn't). Subsequent books set in Benny's home era have offered no evidence of this.
 * In The Neanderthal Parallax, litterally everyone in Neanderthal society is Bi, being expected to take a "man-mate" and a "woman-mate".
 * Word of God about the Liaden Universe novels is that Liadens should be assumed to all be bi. We see several homosexual encounters but all the permanent arrangements we see on screen are heterosexual- unsurprising for a culture that puts huge weight on providing an heir.
 * Swordspoint and The Privilege of the Sword—perhaps not everyone is bi, but the only monosexual major characters are the villainous Lord Ferris (a depraved heterosexual, perhaps?) and, whose straightness may or may not have been caused by childhood trauma (thereby inverting Rape and Switch).
 * Due to the nature of a dragons mating flights and the fact that over 50% of the dragon population are females that mostly take male riders, it's implied that at least 80-90% of dragonriders in Anne McCaffrey's Dragonriders of Pern series are at least bisexual. Only Gold riders (1%) and Bronzeriders (5%) are exclusively heterosexual.
 * In Janet Morris' The High Couch of Silistra and sequels, while being straight seems to be the social norm, homosexual sex is apparently commonplace and completely acceptable. Estri, who begins the novel as a well-woman has a lot of experience servicing men, but when a customer essentially forces her into lesbian sex with another well-woman, she admits to being very aroused by the experience. Chayin and Sereth, two of her primary lovers, also have sex with each other, though only off-screen.
 * In The Culture, considering that the line between species and gender is completely blurred and deconstructed, everyone just seems to go with what they like, no matter what that is. And considering that Culture humanoid citizens can change gender and move into non-humanoid bodies with multiple sexes and... Look, suffice to say that if you brought up sexual orientation to a culture citizen they'd presume you were from a very very backwards planet.
 * This is reflected in their language, which does not differentiate between sexes.
 * In fact, Gurgeh from The Player of Games is considered bizarre because he's straight and has never changed his sex. A friend of his also seen as weird because she spends almost all of her time as female.
 * In The Stone Dance of the Chameleon by Ricardo Pinto, sexuality is pretty much discarded as a point of interest, where straight and gay relationships are equally common-place. The problem comes where you have the Chosen (who are the undisputed 'supreme race' so to speak) and the other races (who act as their slaves and who aren't even allowed to look at their faces). Considering that all subservient races are completely oppressed by the Chosen and horrifically bound by The Law, their tends to be a lot of sexual abuse, rape, and subjugation of both genders of those races ... and some of the stuff the more sadistically-minded Chosen are into crosses the line of 'torture' and becomes Brain Bleach incarnate (Up to Eleven). In fact, when the main character (who is a Chosen, but brought up away from their culture), finds out that another Chosen has raped his half-slave brother, said Chosen can't understand why he's so upset and is genuinely shocked that he cares so much. Nuff said.
 * Arthur C. Clarke's novel Imperial Earth includes a line in which the protagonist's best friend is described as "aggressively normal," because he seems to have no preference between males or females—most people in the late 23rd Century go both ways but have at least a slight inclination toward one gender or the other.
 * Ursula K. Le Guin's story collection A Fisherman of the Inland Sea deals with attempts at instantaneous space travel. The final story, Another Story or a Fisherman of the Inland Sea, introduces the traditional culture of Planet O where pretty much everyone has to be bi for a successful marriage. Marriage is not between two people but four, two men and two women—a man and woman of the Morning moiety and an Evening man and woman. The Morning woman and Evening man, the Evening woman and Morning man, the Morning woman and Evening woman, and the Morning man and Evening man all have sex with each other, meaning every partner in the marriage has a husband and wife from the opposite moiety. (Sex within the moiety is forbidden, so the Morning man/woman and Evening man/woman in the marriage are strictly platonic. In fact, it's perfectly proper for siblings to be the Morning or Evening half of the foursome. Yes, this does mean that you are banging the same woman that your sister is regularly doing, and also the man who would otherwise be your brother-in-law.) The protagonist's mother, a Terran woman of Japanese descent, married in this way to be with the man she loves but finds it strange many years into the marriage, even though she is on good terms with her wife in the marriage.
 * In Palimpsest it's not as much as Everyone Is Bi but "Everyone is so desperate to go back into Palimpsest that they will slept with anybody with the mark, no matter the gender".
 * Many Mary Renault novels fit this trope. She wrote a lot of historical fiction set in ancient Greece, where bisexuality was considered the norm, for males at least. Some of her Greeks are exclusively or near-exclusively heterosexual or homosexual, but many aren't. The characters in her contemporary novels are also often quite flexible about gender.
 * In the Lyremouth Chronicles series by Jane Fletcher, this is the standard situation for the people on the mainland (the islanders have a more mediaeval approach towards same-sex relationships), to the point where being exclusively attracted to a single sex is almost incomprehensible and rather rare. The closest the mainlanders get to homo/heterosexuality is preferring a single sex, which is put on the same level as a preference for tall people, or people with blond(e) hair.

Live Action TV

 * In Torchwood, everyone in the main cast is at the very least bi-curious. The Doctor Who episode that introduces Jack Harkness states that his omnisexuality is common for the century (51st) that he grew up in, in which the Captain Kirk approach to first contact has been the norm for so long that species and gender lines have become muddled. As Steven Moffat explains, it's a future where the whole human race is pansexual. Of the Torchwood gang, Tosh and Owen are properly bisexual, Ianto is either just bi for Jack or lying about not being into men who are not Jack, Suzie is seen snogging Gwen, and Gwen doesn't elaborate on which aspect of being kissed by various female villains weirds her out.
 * A flashback involving two female members of Torchwood 3 in the 19th century (Alice and Emily) shows that they are a lesbian couple. At least one of them may be bi, given that she finds Jack to be pretty, but that may simply require the possession of sight.
 * The Daily Show. Everybody on the show has either shown bisexual tendencies on screen, or simply mentioned having had sex with both genders.
 * More often than not, the bisexuality is played as either comedic misunderstanding themed (Jason Jones once mentions that he married a gay man, after misinterpreting a recent ruling allowing gay marriage) or the correspondent is gay for pay (as seen with Rob Riggle, who had sex with men for money in order to earn the cash to buy an iPhone.)
 * J. Michael Straczynski's philosophy for Babylon 5 was that in 2258, sexual orientation is a non-issue—not that everyone is bi, people just don't make a point of it. He suggested early on that one of the main characters was bisexual. This turned out to be Ivanova, but it only came up a couple of times.
 * Another interesting note is in the Babylon 5 movie River of Souls we find out that a holographic program was created with an image of Captain Lochley. Garibaldi discovers this program is especially popular with women.
 * In a subtler incidence, Marcus and Franklin pose as a newlywed gay couple when undercover on Mars. Nobody considers this unusual, though people aware that it's a cover do consider it funny - not the idea that they might be gay, but because they make such an ill-suited couple.
 * Word of God for Battlestar Galactica is that all Cylons are Bi. This is actually seen in the Three and Six models.
 * In Farscape, sexuality is completely by-passed as an issue. When you have trans-alien relationships, the actual gender of who you're attracted to becomes moot. It's also implied that humans are comparatively very rigid and backward when it comes to sexuality. Both D'Argo and Chiana seem surprised that humans generally start having sex so late (D'Argo first had sex when he was... seven, I think it was?), and Aeryn illustrates how in the Peacekeepers sex is fine as long as it doesn't involve any emotions. Chiana at least certainly doesn't make any distinction...
 * One particularly amusing episode featured an alien who, after being annoying comic relief for 47 minutes, closed out the show by coming on to D'Argo. Up to that point D'Argo and the viewers had assumed the alien was male (the role was filled by a male actor), but she assures everyone that she is in fact female and "Quite the looker." It's not clear whether D'Argo is more turned off by her masculine (by everyone else's standards) appearance or just by her personality. At episode's end Chrichton checks to make sure that Aeryn is in fact "The female of her species," (although he was probably just joking). It's hard to say where this episode puts the cast in terms of this trope, except to demonstrate just how weird and unpredictable ideas like sexual identity and gender roles become in a cross-species environment. If everyone isn't bi, they might as well be, because all terms and definitions are more or less out the window.
 * Chiana is quite obviously Anything That Moves but there are plenty of comments by/about D'Argo in particular that reveal he just might go both ways as well. The two that come immediately to mind are when Chiana proposes that Crichton have sex to get over his writer's block and when asked with whom, Chiana replies "Me, him, whoever", referring to D'Argo. Also, in the episode when John gets married and asks D'Argo to be his best man, D'Argo replies "I'm with Chiana now, John", the implication being that he'd be perfectly willing to be John's best man if he was single.
 * Nip Tuck: Several of the characters have been bisexual and several of the heterosexual men have been raped by other men. Julia becomes a lesbian in season 4 but goes back to her usual two men Christian and later Sean. Liz a staunch lesbian relaxes her standards for Christian...and a male to transexual in the first season. Matt falls in love with Ava a transsexual, almost gets compelled to do gay porn to pay for his meth habit and briefly becomes a prison wife in the final season before reuniting with Ava. Merril Bobolit becomes Escobar Gallardo's prison bitch. Gina is seen to have had sex with several men and one woman in one episode. Kimber as a porn star frequently slept with women for work and frequently had threesomes to make Christian happy. Quentin Costa is a bisexual intersex rapist. Christian was molested by his foster father, raped by the Carver and briefly had gay dreams about his best friend/business partner Sean.

Tabletop Games

 * Exalted - This is common Fanon, even though it's not exactly true. The setting has its share of bisexual characters (as well as straight and gay ones), but since so few mainstream tabletop games even mention sexuality, it can be jarring to see so many be confirmed to go both ways. The fact that it's usually seen as no big deal in-universe probably doesn't help this perception.
 * Maid RPG includes seduction rules that are specifically mentioned as "not in any way governed by gender."
 * Bliss Stage, as the trope namer for Level Up At Intimacy 5, tends to have a lot of this.

Theatre

 * Lashings of Ginger Beer. Ohhhh, Lashings of Ginger Beer.
 * Sleep No More.

Videogames

 * The Sims - For simplicity's sake, every Sim can romance any other Sim, at least as far gender goes. There are some obstacles, but none of these are gender.
 * The Expansion Pack The Sims 2: Nightlife complicates things: positive romantic interactions increase a Sim's invisible attraction score to that gender, allowing better chemistry. Gender preference can also decay, so if your Romance Sim flirts with male Sims all the time, they can suddenly stop being attracted to female Sims. Pretty weird, even for a game like The Sims. Whereas if they flirt with both they will be attracted to both.
 * The issue with The Sims was that a Sim would flirt with everyone. They changed it in 2 so that while a Sim would be amenable to sex with either sex, they would only autonomously have one preferred sex, defaulting to heterosexual but homosexual if the user chose to play them that way.
 * In The Sims 2, Sims are asexual by default untill a romantic intereaction is performed by or on them.
 * The Asari in Mass Effect are a One-Gender Race of blue women who can breed with anyone (any species, any gender). Needless to say, many Asari appear to be bisexual, because they seek people to mate with based on different criteria (with a focus on species, not gender).
 * Not just the Asari but Mass Effect characters in general, particularly 2 and 3 where a number of romancable characters are "open minded".
 * In the unbearably cutesy Animal Crossing clone Magicians Quest Mysterious Times, any classmate can be romanced by either gender, which likely earned it its E10+ rating.
 * World of Warcraft - One of the succubus's abilities, Seduce, can affect males and females equally.
 * During the Valentine's day event, PCs can exchange pledges of adoration with NPCs for love tokens. Gender is only a factor in that female NPCs will romance PCs wearing cologne and male NPCs will romance PCs wearing perfume. Either gender can wear either cologne or perfume. Worth mentioning that to get the Largest prize you need at least twenty pledges from each city, Darnassus is all female and Ironforge is all male. On Horde-side, Silvermoon is all male.
 * In City of Villains, Succubi have a power called "Come Hither" that prevents players from being able to attack them directly. Interestingly, it works on both genders just as easily. The spell is broken immediately if the Succubus attacks the player.
 * Quite possibly the men of Metal Gear Solid, where there are three canon bisexual characters—Colonel Volgin, Vamp, and Dolph himself. There's also subtext between Solid Snake and Otacon despite their own things for the ladies, and while Big Boss has no canonical partner he benefits from Everyone Being Gay For Big Boss with and especially when —hence "Liquid Ocelot"—throughout the events of Metal Gear Solid 4: Guns of the Patriots... all for the cause, all for Big Boss.
 * In Metal Gear Online, both male and female characters can learn the Charm ability which causes them to do a sexy dance, stopping other characters in their tracks. The sexy dance does not discriminate based on gender.
 * Neither do the play-boy magazines
 * Big Boss can also go on a date with Miller at the end of Peace Walker and take photos of him on the beach in a thong.
 * That they have sex afterwards may also be relevant.
 * In the main Pokémon games, "Attract" only works on Pokémon of the opposite gender, but in Pokémon Mystery Dungeon Rescue Team Red and Blue, where only the player character has a definite gender, Attract works on (virtually) everyone.
 * While "Attract" affects only the opposite gender in the main series, the same cannot be said to "Charm" and "Sweet Kiss", though the earlier might apply to the Pokémon's cuteness.
 * Morrowind - NPCs of either gender, everywhere that you go, will greet you with the phrase "I like what I see."( most often delivered in a vaguely creepy tone). This is, of course, regardless of which gender the PC is. Which implies that not only are all residents of Vvardenfall bi, they also all find you irresistibly attractive. Must be that Telvanni Bug Musk...
 * In The Elder Scrolls V: Skyrim, every marryable NPC, male or female, is available to either gender of player. Of course, this gets lampshaded by M'aiq the Liar.
 * In Vampire: The Masquerade Redemption all women, and only the women, are bisexual. Well, there's one token bi guy just at the beginning of the game, and possibly one straight girl. But almost.
 * The second game, Vampire: The Masquerade Bloodlines, takes it further: all of the women are bisexual, except the obvious vamp-bait ones in clubs. These are gay.
 * In the computer game, there are a few straight women (the crazy family towards the end is highly homophobic).
 * In Cupid, you can match up anyone with anyone.
 * Liberal Crime Squad allows you to seduce people of any gender (and you often don't know their gender before you try to seduce them). The chance of success depends solely on your skills.
 * In Star Ocean the Second Story, any of the characters in the party can have romantic feelings for any of the other characters, regardless of gender (or age, or marital status.)
 * In Echo Bazaar, there are storylines that allow the player to romance partners of any and every gender...including at least two threesomes. In fact, the text is always written so the PC's gender never makes a difference; "the Dashing Smuggler slips his arm around your waist", for example. (It helps that the PC's gender can be set as "Gentleman", "Lady" or "There are people walking around with the faces of squid—squid—and you have the nerve to ask me my gender?".)
 * In Dragon Age II, all the main romance options are available to both genders (fairly appropriately, one of them is voiced by Eve Myles from Torchwood). DLC character Sebastian is the only heterosexual-only romance, as well as being non-sexual.
 * Several of the non-romanceable companions are also implied to have bisexual tendencies to varying degrees. Aveline kisses Hawke regardless of gender at the end of her chapter 2 loyalty mission, Bethany expresses some curiosity about Isabela's sexual history with other women and Varric has some slightly flirty dialogue with Anders (though his heart belongs to Bianca, his crossbow). Even Bianca apparently feels some "confusion" when Isabela suggests she needs "a woman's touch on her trigger."
 * In Magical Diary not only can the PC date both male and female options, but many NPCs have explicitly dated both, and no one raises an eyebrow.
 * In Guild Wars 2, the Sylvari are noted to be like this. They're a race of plants mimicking the humanoid form, are incapable of sexual reproduction, and socially have no concept of gender. Developer blogs about Sylvari society and culture have noted that Sylvari consider gender completely irrelevant, including in matters of love.

Webcomics
"Karkat HUMANS HAVE A WORD FOR THAT?
 * Michiko Monogatari
 * By this time, pretty much everyone in Shortpacked has had both a gay and straight experience with the exceptions of the boss Galasso and Ronald Reagan.
 * Faz even refers to the Kinsey scale, although he gets how it works wrong. ("Now, if I have sex with a woman, I will be a 3!")
 * Most of the cast in Sparkling Generation Valkyrie Yuuki have shown or talked about attraction to both genders. The rest aren't confirmed as either bisexuals or monosexuals as of yet. Of course, most of the cast are Norse mythological figures, where this trope also applies.
 * Most drows of Drowtales are bisexual. However, only heterosexual and lesbian couples appear in the main comics.
 * El Goonish Shive is a funny case, since characters who have been genderbent by Tedd's TF Gun develop a temporary attraction to the opposite gender. Depending on how you look at it, between one and two characters are naturally bisexual (Ellen is an Opposite Sex Clone who has all the memories of her original male heterosexual self, and hasn't fully come to terms with the fact that she's attracted to guys as well as to girls. Grace is "Teddsexual" regardless of Tedd's current gender.), but seven of them have been genderbent, and of those the four straight ones have all had to deal with attraction to both genders. (Justin and Nanase are exempt from this due to being naturally gay—when genderbent, they just get even more attracted to guys and girls, respectively.)
 * While only two characters in Ghastlys Ghastly Comic have ever been called "bisexual", almost every cast member has slept with, kissed, or had a Stupid Sexy Flanders moment with members of both sexes at one point or another.
 * Concession: not everyone is bi, but a large proportion of the cast are. Joel, Matt, Roland, Angie, Emily, and Chelsie are all described as bisexual on their cast pages. Nicole (who is actually a male named Aaron), Cecil, and Kelly are gay. The other ten characters named on the cast page are heterosexual - so, not everyone, but a much higher proportion than real life. A remarkably high proportion of gay and bi characters show up in the randomly generated background character population as well.
 * A few heterosexual characters have had homosexual encounters though, such as Artie's drunken foursome that included another guy.
 * And recently  let slip that he has had "hot gay sex" at least once, his girlfriend was not happy.
 * Word of God for The Challenges of Zona is that the Erogenians practice "situational bisexuality" as a matter of course and that Zona and Tula have had lovers of both sexes.
 * Ménage à 3 starts out with a varied cast of gay and straight guys/girls with one Bi girl. By now, every single named character (and plenty of one-off extras) has had at least two or three instances where they've shown more than a little attraction for both genders, with the exception of the landlady and the guy who stays indoors and thinks it's still the 80's.
 * Homestuck. Troll reproduction centers around emotional relationships rather than a combination of biological equipment, so any pairing is viable for breeding, and sex is pretty much cosmetic. One troll (Karkat) even shows astonishment when the human characters try to explain the concept of monosexuality to him.

John Yes.

Karkat HOW IS THAT EVEN A THING?

John shrug. it just is.

Karkat HUMAN ROMANCE SURE IS WEIRD."


 * Much to the delight of the comic's sizable yuri and yaoi fanbases.
 * According to Word of God, it is possible for a Troll to be monosexual, but they don't recognise it the same way we do- whereas heterosexual humans would deny advances from someone of the same sex because they are heterosexual, a heterosexual troll would do so because they don't find them attractive. It's more like a kink or fetish for either gender than anything else.
 * The comic as a whole only has four characters who are explicitly not bisexual: John who is "not a homosexual", Kanaya, who is gay, Doc Scratch, who has neither gender nor sexuality, and finally Dirk, who is possibly the most Badass Gay in existence. And even apart from the trolls, there's, who is also bi.
 * Played with a bit later on, with Dirk preferring the troll way of ignoring gender and sexuality and just being attracted to whoever you're attracted to and Roxy insisting that for humans, at least, sexuality is very much a thing.
 * In Curvy everyone seems capable of making out and having sex with virtually anyone else, on a moment's notice.

Web Original

 * Dirty Potter
 * Applies to all the male characters of Yu-Gi-Oh the Abridged Series with the exception of Pegasus, who plays Camp Gay to cover up his heterosexuality.
 * Vocaloid has this in spades.
 * TV Tropes, more often than you'd suspect.
 * Almost everyone on That Guy With The Glasses will flirt or perv on a person of their own gender if it aids a joke or Fan Service.
 * Gaia Online's Valentines 2009 event allowed the users to send Valentines to a number of NPCs, who would respond or refuse according to programmed turn-ons or turn-offs. Liam, Devin, and Vanessa refused Valentines based on the sex of the avatar who sent it to them; everyone else had qualifications based on other things and would respond regardless of gender.
 * In addition, there have been three Chance Item sets based on Dating Sims. The user can freely choose whether to pursue a male or female love interest in each, and none of the interests are restricted by the user's gender.

Western Animation
"Gilette:Girl please, no one is that gay."
 * Drawn Together - Every cast member seems to have slept with or kissed at least one other character of the same sex.
 * The Simpsons - Often male cast members will show attraction to other men. Especially if it's funny. ("It feels like I'm wearing nothing at all. Nothing at all. Nothing at all!")
 * Superjail. Maybe? It's not even entirely clear about the gender of the collective main cast. In any case, no one seems to be deterred in their crushes by little things like transsexuality or gender-switched counterparts from another planet/dimension or people who can apparently spontaneously give birth through their anuses. Or death.
 * Agent Gilette of Archer is a fairly typical gay stereotype, complete with fruity accent. But even he would line up to get busy with Lana

Real Life
"Cicero: Enough of that. It is well known what you gave him...and what he gave you."
 * Scientist Alfred Kinsey's theories postulated that the great majority of the human race was bisexual in some shape or form.
 * More specifically, he came to believe that sexuality was a sliding scale rather than something with cleanly cut categories, and that nearly nobody is completely to one end of the scale. One might prefer one gender, but most will find the other gender attractive to some degree (Stupid Sexy Flanders).
 * Recent studies measuring genital arousal tend to find non-zero arousal to all types of human sexual images. This is sometimes suggested to reflect situational embarrassment, but it could also have real implications for how our sexual responses work.
 * Literally true in some animal species, for instance the Bonobos and dolphins.
 * Not that it can actually be proven, but /b/'s existence and culture is largely inexplicable without a large number of /b/tards being bisexual on some level.
 * Also, pun.
 * The ancient Romans defined sexuality less by your partner's gender than by whether or not they were actually Roman.
 * Also, at least for men, sexuality was much more defined by who was topping than by gender. (Some of this attitude still persists today, for instance in jails.)
 * In terms of sex, it was considered socially acceptable to have sex with, say, an attractive slave boy, as long as you were doing the penetrating. But even then, many would have regarded it as a decadent foreign (i.e. Greek) practice. But under no circumstances would it be acceptable to have an openly homosexual relationship with a free person, citizen or not. Not to say it didn't happen, but it would definitely be a secret.
 * There were examples of Romans being publicly known to be on the receiving end, as it were (including at least one Emperor), but it was considered extremely scandalous.
 * This was actually pretty typical of various ancient societies, where it can seem from the modern perspective that Everyone Is Bi, when in fact it's more a case of Blue And Orange Sexuality, to borrow a metaphor.
 * Julius Caesar's Berserk Button was people saying that he had been the submissive partner in a relationship with the King of Bitynia. Cicero summed it up, when Caesar was pleading for Roman support of the man:


 * Ancient Spartans were more or less required to be bisexual. A Spartan boy's first relationship was expected to be with an older man, who would act alternately as father figure and lover, and there were several laws regulating the nature of this relationship (such as "if a boy is courted by two men, and he chooses the richer, he has to pay a fine"). By contrast, a Spartiate would have an Arranged Marriage with a woman he didn't know and be expected to consummate it in secret (though later they would be allowed to live together as a family). Things are less clear on the female end, but several hymns relating to women and their yearning for "choral leaders" exist..
 * There have been some writings that tell of the women shaving their heads, so their soon-to-be-husbands can ease into the idea of a sexual relationship with a woman.
 * Part of Ron White's stand-up routine involves this trope.
 * There's a joke that goes like this: "If you give people two choices in flavors, nobody will stick to one just because they're told to".
 * Freud said that humans have a predisposition toward bisexuality, but become monosexual through psychological development, while the bisexuality remains in a latent state. In other words, Everyone Is Bi.
 * Some, male or female, believe this is true about women.
 * Danni Ashe, adult model and businesswoman, frequently conducts interviews with other adult models on her website. In these interviews the question of sexuality inevitably comes up, and the answer is inevitably some variation of being bisexual. Like, nearly every single one. Whether they're being honest is up to the viewer...