Sometimes things get Lost in Translation, and occasionally this isn't so much "lost" as "purposely altered". Sometimes the "thing" in question is a character's sex.
Reasons for this are generally narrowed to five:
The work is being translated into a language that uses the concept of grammatical gender for nouns, and the character's sex doesn't fit the grammatical gender of their name, so the translator changed their sex because he thought it would otherwise look unnatural. This usually applies only to animals, objects, and Anthropomorphic Personifications.
The Honey Pops cereal mascot Pops is male in some European countries.
Anime and Manga
Zoisite from Sailor Moon was a flamboyant male in love with Kunzite (Malachite) in the original anime, but was changed into the female Zoycite in the DiC dub (and most others). At least the voice actress was competent and gave "her" serious schadenfreude. In the Italian dub, they removed the Gender Bender element of the Sailor Starlights by having the Three Lights "replaced by their twin sisters" instead of transform. Presumably, they hung out in Hammer Space until they were called on or something. In France and Mexico, Zoisite and Malachite were brothers, in the original manga the two were portrayed to have brotherly affection (if even that, given they barely interacted at all) so this change is probably the least of an alteration.
The Polish dub made him genderless, with a neutral voice and no pronouns!
Fish Eye was also made female, but it was pretty obvious that the change was made purely as an obligation to appease the moral guardians regarding his cheerful homosexuality; when posing as a fussy primadonna fashion model, "she" throws off "her" shirt, and no one comments on how flat "her" chest is, and no attempt at censorship was made to cover the exposed (if very understated) nipples. The dub DID censor Fish Eye's exposed chest on subsequent airings, however the uncut dvds use the same dub track that the tv airings use, so the uncut dub on dvd shows "her" exposed man-chest while still referring to her as female. However even still there were several shots that made it obvious that Fish Eye was suspiciously flat chested.
In the Polish version, before becoming the fashion model, Fisheye announces that "she" will "become a man" for this task, making it look like "she" is capable of changing "her" sex.
The real kicker about that one is that Fish Eye is capable of changing his sex— or at least some incredibly convincing crossdressing. In one episode where he poses as a ballerina, not only is he an exceptional dancer, but also has some impressive "talent".
Interestingly, the manga never changes either character's gender. Neither Zoisite nor Fisheye are gay men in the manga either...but they are both deliberately designed to be so androgynous they can easily pass for women. Zoisite in particular poses as a glamorous female scientist in one of his schemes to get the Silver Crystal, and Fisheye is listed in the artbooks as being the circus ball girl. Furthermore, their sexual preferences aren't elaborated on either - Zoisite being a love interest for Ami was scrapped before his first appearance and exists only as a concept in an artbook and some of the musicals. Fisheye attempts to seduce Ami, but only to kill her. And of course, the idea of them being bisexual is never ruled out. The anime clearly chose to run with their androgyny to the point of them being sexually attracted to men, but it didn't invent it from whole cloth either.
There had also been several occasions of a character's gender changed for no good reason. Tamasaburo from a filler episode of Sailor Moon S got changed into a girl in at least the Cloverway English and Russian dubs, in the first case due to a very brief crossdressing scene that would have been easier to cut, and Chibi-Usa originally had a crush on him ("cousins", eh?). Zirconia became male in some adaptations, even though she was female in Japan (supposedly, her obsession with Nehelennia's beauty made her come off as a lesbian but she really IS Nehelennia, or at least the personification of her vanity). Queen Metaria got a male voice in the Russian dub, and was referred to as "King Metallia" (maybe the translators intended to make her a royal couple with Queen Beryl?). The Portugese dub wound up with some very amusing Ho Yay moments when they reversed the genders of the cats Luna and Artemis because of all the plots with Luna falling in love with human men and Artemis' ongoing crush on his owner Minako.
What's really hilarious to note about Tamasaburo's gender change is that Rini's crush on him/her remains intact in the dub. Good job, Cloverway, usually you're trying horribly to hide lesbian relationships, and now you just created a new one!
Of course, Japanese Tamasaburo looks like this◊ and is voiced by a woman, using a grown-woman voice and not a little boy voice. It's easy to miss his gender until the very last line in the episode, where "Sailor Tamasaburo" gives his version of Sailor Moon's introductory speech, but "bishojo" is replaced with "bishonen" in his version of the full title.
In the French dub, the secret identity of Sailor Uranus is called Frederique and has a male voice, which changes to female after transformation. Though spelling it "Frederique" still makes it a female name. The male spelling is "Frederic".
The Russian dub of Sailor Stars left the Starlights as they were (male in civilian form, female when transformed — with two sets of voices, even)... and added the same quirk to poor Haruka, who was voiced by a man in civilian form. The best part is that this change made no sense: Haruka was already acknowledged to be female (and in relationship with Michiru) in the third season, which was translated several years before by a different company; apparently, the new translators were not familiar with the previous translation — let alone the original — considering how many names and spells were screwed up in the transition.
Ruby Moon in Cardcaptor Sakura was originally genderless and preferred girls' clothes as Nakuru Akizuki. The Nelvana dub just made her female.
Renamon's genderswap was even lampshaded (sorta) in one episode. "He" explained that while Digimon can be gendered, they don't have biological sexes. Rika's mother then replied that "he" looks very feminine.
The Spanish voice actress for Renamon sounds blatantly throaty and male, producing confusion about her gender for a while. After evolving into Sakuyamon, though, it would be hard to picture her as a guy again...
Hungary didn't even try to have Renamon be Female. So they got two men (Gábor Varga and Gábor Seder) to voice him.
Digimon Frontier's Lord/RhodoKnightmon was a male, but the dub's Crusadermon was female. Probably because RhodoKnightmon, like the mineral rhodonite, is pink, constantly describing things as "beautiful", and is about as close to Camp Gay as you can find in a Digimon series.
Tailmon/Gatomon from Digimon Adventure was almost dubbed as a boy until the script writers luckily saw the following episodes where she evolves into AngeWOmon.
Lopmon in Digimon Tamers was male in the Japanese version but female in the US version. This is one of those rare cases in which you can't really blame the dubbers at all. In Japanese, Lopmon's gender was fairly ambiguous: he was voiced by a woman, had a brown/pink color scheme, was partnered with a little girl Tamer, and to top it all off, used an outdated honorific dialect with no gender-specific pronouns. The dubbers took a guess, and missed. What confirmed his gender was a scene of Shiuchon instructing him to use a male "I" pronoun (changed to Suzie instructing Lopmon on how to be properly childlike), but by then, several episodes in which Lopmon was referred to as a "she" had already been broadcast in America and it couldn't be changed.
The Filipino dub of Digimon Adventure 02 mistook Daisuke's older sister, Jun, for a male (likely because the name "Jun" is commonly a boy's name in the Philippines and because of the rather androgynous body types of most young females in the series) and gave her a male voice actor in her first appearance. All succeeding episodes, however, rectified this, with no explanation at all as to the sudden change in voice gender.
Nitro Convoy from Transformers: Galaxy Force became the female Override for the dub Transformers Cybertron. They also did this with a generic motorcycle refugee; her Tfwiki.net article even has a link to this page.
In the Hungarian dub (translated from the English version, not the Japanese), Override started out as a male, but no one noticed the weirdness because of the gender-neutral pronouns. Then Bud referred to "him" as a "chick" at one point. The show took a long break without any new episodes airing, and when it continued, Override became female, and likewise, other characters also received new voices.
This is made even more ridiculous by the fact that this was a direct-to-DVD dub, which usually serves as an (additional) point of getting the people who already have the fansubs to buy the DVD. Needless to say, the dubbing company did not even care enough to redub the wrongly-dubbed parts after The Reveal. Would've costed money, you know...
In Naruto Yashamaru, Gaara's androgynous uncle that looks like his mother was made a woman in the Italian and Polish version of the manga (though apparently not the anime). Of course, in the versions where he wasn't changed, the only real way to actually know he was male was when either a character referred to him as such (especially the manga, where you couldn't even tell his gender by his voice).
In Japan, Yashamaru was voiced by the same guy who did Kazuki in Get Backers. No surprises then.
The "-maru" kind of gives it away. If you know Japanese naming conventions.
Supposedly Shiore, the grass ninja from the Chunin exam that was really Orochimaru in disguise, was changed from male to female in the English dub (he/she definitely did have a female voice actor). This is hard to say, as Shiore said little, was talked about little, and is incredibly androgynous.
Incredibly, the decidedly female-looking Kurenai spoke in a male's voice at her first appearance in the first Hungarian dub. The second dubbing team payed more attention.
In a few dubs of the anime, notably the Serbian one, Haku is refered to as female and has a female voice actor.
The Filipino YuYu Hakusho dub (renamed "Ghost Fighter") is rather infamous for this. Originally, Kurama was thought to be a girl, dubbed by a female voice actor, and named Denise. They hand waved it later, by explaining no, his name's really Dennis and he impersonates a girl while in the human world — then this is, apparently, never spoken of again. Worse was Old Master Genkai, dubbed as Master Jeremiah, and thought to be a man. It must have been strange when he suddenly turned into a Megumi Hayashibara-voiced (okay, not in the dub), pink-haired young girl.
The Kurama thing was apparently figured out in a scene where he rips his shirt open, revealing a very flat male chest. Apparently the fact that he's always running around in a BOY'S uniform never caught their attention.
Also present in the Hungarian dub: Kurama has a deep-voiced female voice actor and the lack of gender-specific pronouns in the language make it even more ambiguous.
There's also the matter of the demon Miyuki of the Triad, the Elite Mooks of the Toguro brothers' gang. In the original Japanese and the unedited English dub, he's a man who crossdresses and is heavily implied to have breast implants (or a woman who was undergoing gender reassignment surgery). In the edited English dub, she's a woman who fakes her injuries so men will feel guilty about beating up a woman and back down just as "she's" about to attack them again. Leads to a nice display of Wouldn't Hit a Girl and Would Hit a Girl in either case.
The Fruits Basket anime Overtook the Manga and instead of giving it a Gecko Ending they simply concluded the story about halfway through the manga material. However, at the very end of the manga it is revealed that one of the major male characters was actually a female all along, raised as the opposite gender. In both the original Japanese language version and the English dub, the character has a completely unambiguous male voice. Of course, the point is moot because of where the anime ended, but still…
He's clearly shown with a male chest at one point.
In the French dub of Pokémon, the recurring Jigglypuff is a male.
Also, Ash's Chikorita was male in the Spanish dub (and he was in love with Ash...).
Melissa from the Kanto League (the Trainer who eventually beat Gary before Ash did) is female in the dub. Not only is HE voiced by a guy in the Japanese version and a woman in the dub, from the side, he unmistakably looks like a guy, even having a masculine Japanese name (Yoshiki).
Despite Ash's Staravia's gender being confirmed, he's female in the Czech dub and male everywhere else. It's even confusing where in Jumping Rocket Ship, he encounters what appears to be a Staravia with a girl's bow, as well as falling in love with her, thinking she's real.
In many foreign dubs, Pokémon have defined genders, since there are many languages that don't have ambiguous pronouns. A good example is the Brazilian Portuguese dub - there is no "it" in the Portuguese language, only "he" and "she". Therefore, all Pokémon got genders. Usually they went with the everyone-is-male rule, unless the Pokémon showed some attraction for someone of the masculine gender (Chikorita, for example).
In the Hindi dub, Brock's Happiny was referred to as a male. Happiny cannot ever bemale in the games.
Hun from The Legend of Thunder! special, causing quite a bit of frustration among fans. However, he was never explicitly referred to as a woman in the English dub, he just had a female voice. He is unambiguously female in languages that are loaded with gender-specific words, though.
Pokémon Diamond and Pearl Adventure! has an odd variation where Commander Saturn is refered to as female twice on one page, but male in every other instance. It becomes partially understandable when you realize that a few pages earlier he was drawn with broad hips, long eyelashes, and what appears to be boobs.
In the Chuang-Yi version of Pokémon Special, Tate mistakenly referred as a girl. Strange since the artist drew girls with longer eyelashes than boys and Tate was usually shown standing next to his sister, Liza.
In the Italian and Spanish dubs of Mermaid Melody Pichi Pichi Pitch, Villainous Crossdresser Lady Bat was changed into a female. However, in episode 16 the scene of him winking at Coco (complete with hearts coming from the eye) was not cut out. This is funny in Italy if you consider that they repeatedly cut out certain scenes between the Black Beauty Sisters (including that scene when they're about to kiss while singing. Spain kept them). Essentially, they censored two lesbians but they created another one. To make things even more ridiculous, in the Italian translation of the manga, Hanon asks Lady Bat "if you are a girl, then why are you dressing like a boy?" (Of course, in the original manga it was the opposite). A skirt and a pair of high-heeled boots is very manly, indeed.
Also, hilariously, he actually dresses up as a guy in two late episodes, making "her" a crossdresser regardless.
In the USA-produced Latin American dub of Magic Knight Rayearth, Autozam's commander, Eagle Vision, was changed from a man to a woman. While this played all sorts of havoc with the Love Triangle — turning the Yaoi Guys into a heterosexual crush, and accidentally turning Lucy (Hikaru) into a Schoolgirl Lesbian — many fans of the series thought the strong performance by the actress and the change into a female military commander (with giant mecha and all) yielded a more interesting character overall.
The Latin-American dubs for Hunter × Hunter and Sakura Taisen did the characters Illumi Zaoldyeck (voiced by a female in the dub, referred to as female despite being male in the original) and Leni Milchstrasse (voiced by a male in the dub, referred to as male despite being female in the original). Both cases were a mistake, since both series were dubbed by the same company, which also dubbed Rurouni Kenshin and kept both Kamatari's gender and homosexuality intact.
The Brazilian dub did many times, as well:
In the Shaman King dub, the first cameo of the Big Bad Hao was a still picture, where he covered his face with his cape. He has a single line in the scene. Since the evidence wasn't enough to say he is a man, he got a very female voice to say the line. In later appearances he has a perfectly normal male voice, ignoring previous change.
Also, Kororo was voiced by a male voice actor and referred to as male, even though it's revealed in manga she used to be a human girl while alive. But the one that takes the cake is Goldva, which was correctly voiced by a female voice actor in her first and short appearance... but then was treated as a male for the rest of the series, completely masculine voice included.
In the InuYasha dub, Hakudoushi was first thought as a woman, and also got a very female voice actress. Later he is referenced to as a boy (suddenly)... but they kept the very female voice actress anyway.
Hunter × Hunter: Strangely, despite getting Illumi and Kalluto's gender right, they treated Senritsu as a male in the Brazilian Dub, complete with unmistakenly male voice. The Brazilian version of the manga also made Neferpitou a female.
In Shaman King's Latin American dub, Goldba is given a rather elderly male voice in her first (and brief) appearance in the anime, and is later corrected when she reappears several chapters later.
CLAMP has a thing for genderless characters; the angels in Wish are genderless too, so long as the translated languages had genderless pronouns. Other times Kohaku was referred to as female (Tokyo Pop) or male (French Canadian?). Confusing the whole bit is the presence of the tightly-dressed cat demons, who look distinct from them and are very clearly female.
The Spanish translations of Wish and RG Veda have turned the androgynous characters (Kohaku and Hisui in the former, Ashura in the latter) to feminine, too.
Interestingly, Kohaku appears in the Japanese anime for Kobato. Kohaku's female seiyuu has a VERY feminine voice and the animation is far less ambiguous than the manga artwork.
Tokyo Pop made another mess when Quiche ("Kish") in Tokyo Mew Mew referred to Tart as a "witch" in his first appearance. Given the male villains' revealing uniforms, an open top had unfortunate implications, so it's lucky that he was reverted to a boy when they figured it out.
More fun with Tokyo Pop. In his first appearance, Get Backers' obligatory Bishōnen and usually unwilling Crossdresser, Kazuki, was referred to as a bitch, a seamstress, and a she. (Not that Shido calling him a bitch wasn't hilarious in its own way.) They corrected this in his later appearances (and good thing, too, since there's a scene where he's both a) naked and b) explaining why he carries himself like a girl), however, and changed his nickname from "Kazuki the Seamstress" to the gender-neutral (and better translated) "Kazuki of the Strings." ADV, the company that dubbed the anime version, avoided this by actually watching the series, apparently. The DVD Commentary has a joke to the tune of "Well, as the writer, you make all the unexpected discoveries first..." / "Yeah, and one of the most unexpected is that Kazuki is a guy."
Tokyo Pop also fixed the error in Kazuki's introductory volume for later printings, making the original printings with the errors somewhat of a prize in the fandom, if just for the comedic value.
And yet more from Tokyo Pop! In their translation of Gundam SEED Astray, primary antagonist Rondo Ghina Sahaku is referred to as "she", "bitch", and "sister". No points for guessing Ghina's gender in the original manga. Their official website even refers to Ghina as "androgynous", which is technically true, but comes off as justification for their mistake. Amusingly enough, the official Japanese website quite distinctly marks Ghina with a male symbol, and voiced adaptations is played by the same person who played Zeta Gundam protagonist Kamille Vidan - who was himself mocked for having a girl's name.
Apparently due to a mistake, Kouhei and Youhei Tanaka from The Prince of Tennis are girls in the Latin-American dub.
This is especially amusing, considering PoT isn't well-known for girl characters to begin with.
Used with Little Arturo and one of the Amoeba Boys, who are male in the original American cartoon, but girls in the anime. Arturo was changed back to male in the English dub of Z, but kept his dress and feminine voice.
This was a problem for some time with Zophise (Zofis) in Zatch Bell!. Lack of gender-specific pronouns, a feminine countenance and a female VA in the anime caused many scanlations and fansubs to assume Zophise was female, but Word of God set the record straight - Zophise is male.
The Cat King's main messenger in The Cat Returns has a distinctly female voice in Japanese and a distinctly male voice in English. The cat's appearance seems to be modeled loosely on an archetypal Japanese female servant, but the character's clownish function in the movie must have seemed better suited to a male in America.
In the English dub of The Cat Returns, the cat servant Natoru is male and voiced by Andy Richter, but in the original Japanese version and most other dubs, the character is female, although the character does behave rather flamboyantly in the English version.
Many European translations of Dragon Ball Z initially refers to Zarbon as a woman, and has him randomly change sex in vol 23. Since all of them are based off each other, and none of them bother changing dialogue in reissues of older volumes, the error keeps sticking around.
The Filipino dub goes so far as to rename "her" Zara.
Technically Puar is this in the English dub, being referred to as "she" a couple times, but in the Japanese version Puar only had Ambiguous Gender and the character was only even confirmed male by Word of God.
Dragon Ball Z Abridged: Dodoria, male in the series, was turned into a girl for the abridged series. Unlike these examples, though, this was Played for Laughs to invoke Unsettling Gender-Reveal. (And also because the 'canon' reveal of Frieza destroying Vegeta's home planet was already common knowledge in the abridged series.)
Dodoria became a woman (granted, with a very deep voice) in the Hungarian dub, probably due to "her" pink color, big lips and feminine-sounding name. Frieza also almost became a female, as his name was at first rendered as "Dermesztina" or "Freeze-Tina", but they switched to the gender-neutral "Dermesztő" ("Freezer") before the character actually appeared, and when he did, he got a male voice. For the record, Zarbon was voiced by a male in this dub, though he softened his voice so much that his gender became indeterminable.
Also Korin the cat from the same dub. Not only did he get a female voice, he was also referred to as a woman in the dialog.
In an episode of Yu-Gi-Oh! Yugi mentions that the card he finds most similar to himself is Maha Vailo, which he refers to as a male (and is dubbed with a male voice when it's used later in the show). In Japan, however, the creature on the card is female, a fact which Yugi admits to being embarrassed about. (Another clue to its true gender is the fact that Anzu uses it, and her deck seems to be composed exclusively of female monsters.)
Tigrerra from Bakugan is subjected to this trope, which becomes painfully obvious when "she" becomes Blade Tigrerra. also, Ingram from the New Vestroia series has a female voice despite a clearly male body, which can only suggest that while the second series was being animated, Ingram was intended to be male, but was made female to seem like more of a successor to Skyress, Shun's former partner
Ingram's situation was made WORSE when s/he evolved into Master Ingram...with a male voice to boot! Fixed but broken at the same time!!
According to Bakugan Wiki, Tigrerra's Japanese name is Tigress.
The German One Piece manga turned Hachi female in his first appearance. After he showed up again after falling in love with an obviously female Octopus Woman, he was treated as a guy, without any comment. In the anime, the spherical Satori was a woman—what makes this a bit awkward is that Sanji had no problem with cracking Satori's skull.
Holy is female in the Danish translation. Though a mistake, it's not the worst gender confusion that could have happened, since his gender doesn't play a role to the story anyways, and you cannot at all tell his gender since he is another of those animals without attributes.
In Zoids: New Century Zero, Harry Champ's Robot, Benjamin, falls in love with a Judge Man robot. The dub alters this to be a female Judge Man, whilst leaving all the others shown male. They could have at least made a couple of the other Judges shown to be the 'female variant'.
Specifically, Crona is intentionally of Ambiguous Gender, yet is referred to with male pronouns in the official English releases of the manga and anime. In both cases, the translators acknowledge that Crona is supposed to be of either gender and admit that they themselves don't know which could be the right one, but because only Medusa has the jurisdiction of calling Crona "it", they had to pick a gender because dodging pronouns would lead to some very awkward sentence structure.
In the original Gatchaman, the villain Berg Kattse was a hermaphrodite, able to take on a male or female appearance. For the original dub into English, Battle of the Planets, The two appearances became two characters, twin siblings; Zoltar and Malanote Although "Mala" was only used for two of female Katse's appearances in that version. In two other episodes, she was a random agent called "S-9", and another referred to her as "Hannah". Neither of these apparent other women were given a familial connection to Zoltar.. However one of the last episodes shown in the US did have the scene where Zoltar/Berg is partially unmasked before escaping leaving the characters to wonder if Zoltar was a woman. Its possible if the US version had continued, they would've just said Zoltar was a female cross dresser.
When Gatchaman II was adapted into Eagle Riders, the female (but very masculine voiced) villain Gel Sadra became the male Mallanox. When the character's gender became more obvious in the later episodes, Saban tried to rectify the error by giving Mallanox a feminine voice (except when in her costume) and referring to the villain with female pronouns.
The French dub of Gatchaman II (Gatchaman: Le Combat des Galaxies) referred to Gel Sadra as "neither man nor woman", but while referring to the young girl (Sammie) that she was mutated from as a boy.
A Korean compilation film adaptation of Gatchaman II had Gel Sadra as a man, and had altered and redrawn footage of his origin: Instead of showing a young blonde girl being grown into the villain, it was a brunet boy named Marko.
The Latin American dub of Rurouni Kenshin did this to Souji Okita, who the translator apparently didn't realize was a real historical figure.
The Hungarian dub of Bleach, which accidentally turned Kiyone into a man for the first few episodes she appeared in. A gay man. They eventually corrected this after noticing what the fans have been nagging them about for weeks: She's got boobs.
The Hungarian dub of YuYu Hakusho played it straight, turing Kurama into a woman, for at least the entirety of the first season.
The Japanese version of the Black Cat manga portrays Shiki as a female, but in the English manga by Viz is male. The anime notably averts this, as he's a man in both versions.
In Duel Masters, the character Shinoji, who is female in Japan, was given a gravelly male voice in the dub.
In Loups=Garous, Ayumi is a girl in Japan, but in the dub is voiced by a male actor and referred to with male pronouns, which gets a little bit confusing late in the movie.
Certain Inazuma Eleven characters like Fuusuke ("Bryce") and Ryou ("Miles") were changed into girls for the dub. It's averted in the English games though.
Rem is a female shinigami in Death Note, although she was voiced by a man in the live-action films (which predated the anime adaptation) while the reference to being female is removed. In the dub of movie 2, Rem is directly referred to with male pronouns to go along with his voice.
In Romeo's Blue Skies, Nikita was a tough little kid who opposed the protagonist Romeo and his group. Although a female seiyu voiced Nikita, it was only near the end of the series that Alfredo exposed Nikita as a girl. Which is fine, except that in the Filipino dub, the network that dubbed the show used a young boy to voice her until the final episode, when a female dubber took over. There was no way to tell the difference until it was too late, anyway.
In the English dub of Sasami Magical Girls Club, Amitav's evil counterpart is clearly feminine and referred to as a female. The Japanese dub hints more at it being a guy, which doesn't help because Amitav looks quite feminine already.
The first run of the Mahou Sensei Negima! manga mistakenly identifies Kotaro as a girl for a chapter or two. Later reprints fixed this.
When Fawcett stopped producing superhero comics after losing their legal battle with DC, publishers L. Miller & Son, who had up until then reprinted the Captain Marvel stories for the British market, decided to continue with home-produced replacements. For Captain Marvel, British readers got Marvelman, for Captain Marvel Jr. Young Marvelman, and for Mary Marvel ...Kid Marvelman. The editor thought a British equivalent to Mary Marvel would not be as popular with his young boy readers.
Lucky Luke's horse, Jolly Jumper, is a mare called Dolly in Greece. It is interesting that this gender change never conflicted with the story or caused confusion and as a result most people in the country consider the horse a female character. ...Until the #73th issue was translated, which was all about Jolly falling in love with a mare. To avoid making 'Dolly' a lesbian, the publishers decided to correct the horse's gender from that issue and onwards.
Madame Rose, the villainess of the Thai film Tom Yum Goong, is a transwoman in the original; in the English release, all references to this are removed.
Mothra Leo in the Rebirth Of Mothra trilogies is a male in the original Japanese dub, but is referred to as a female in the English Dub.
In the Russian dub of Wreck-It Ralph, all of the Sugar Rush racers are referred to as girls, though Rancis (renamed "Slasta") still has a masculine voice.
The Dutch dub renames Swizzle Malarkey to "Savanna Sweettooth", changing him from a boy to a girl. Rancis and Gloyd also become girls, and are respectively renamed "Renske" and "Trijn".
In the original Hungarian dub of The Seventh Brother the Magpie is a male character but in the English version it's female.
In the English version of Watership Down the cat is female but in the Italian dub she's a male character.
The Dutch film Als je begrijpt wat ik bedoel, an adaptation of the comic strip Tom Puss, features the titular character with a cutesy appearance and female voice but he's otherwise male. When the film was dubbed in English a few years later as The Dragon That Wasn't (Or Was He?), Tom was renamed Kit Cat and changed to female.
In the first .hack//AI Buster novel, Watarai's assistant is made male by Tokyo Pop. No big deal, just a passing character, right? Ooooooor maybe it's the very femaleKamui, the Knight Templar bad guy of Legend Of The Twilight. Handwaved, since the series has documented players playing the opposite gender on a few occasions.
Douglas Hofstadter's book Gödel, Escher, Bach features a series of dialogues featuring Achilles and the Tortoise from Lewis Carroll 's "What the Tortoise Said to Achilles." Like Carroll, Hofstadter wrote the Tortoise as male without thinking too much about it (because animals are Always Male). When GEB was translated into other languages, however, such as French and Italian, in which "tortoise" is a feminine noun, the translators made the Tortoise into a female character (Madame Tortue, Signorina Tartaruga). Hofstadter, who had subsequently become interested in the problem of sexism in language such as the male-default for characters in stories, was delighted by this. The episode is discussed in his book on translation, Le Ton beau de Marot.
In various translations (such as the Spanish ones) Terry Pratchett's Death from the Discworld series was given female pronouns, usually due to Death being personified as female in many countries (which in turn is because "la mort" is a feminine noun). This has mostly been fixed in the translations of his more recent books.
The French translations of the earlier books all feature a footnote pun about Death being male because he's a necessary evil* "la Mort est mâle, car c'est un mal nécessaire"; the French words for "male" and "evil" sound the same. In later books, though, the footnote is still here, but basically saying, "Yes, Death is masculine. That's just the way it is." In further books, the footnote comments on the fact that the reader should know this by now.
The Spanish translation of Reaper Man, faced with Bill Door and his not-quite-romance with Miss Flitworth, had a footnote saying, essentially, yes, Death was female in the early books, but now he's male.
The Italian translation zigzagged this trope: earlier translations treat Death as female (for example, in Mort Ysabel calls her "Mommy" and not Daddy), but newer translations (like Reaper Man and Lords and Ladies) treats Morte as a proper noun with masculine pronouns.
In the Italian translation of The Ancestral Trail, the (female) Guardian of Insects Kika was changed to a male.
A rare case of this happening within the same language: John Benson's 1640 edition of Shakespeare's sonnets messes about with them considerably, including changing a few pronouns so that the sonnets adressed to the Fair Lord were now adressed to a woman, turning the borderline homoeroticism into straight-up love poetry.
In Soviet Russia (and most likely in Russia to this day), Bagheera the black panther is female, in both the book and the movie of The Jungle Book. Same with the White Cobra. This particular sex change may have happened for linguistic reasons: in Russian, nouns that end with the vowel -a are (in most cases) grammatically feminine — such as the word pantera (panther), and the name "Bagheera" itself.
On the other hand, the Spanish version (of the Disney movie at least) averts it, despite nouns ending in -a and the word pantera being also femenine.
Likewise, Owl ("Sova" in Russian) from Winnie the Pooh is female, for similar reasons.
Owl also became a female in Polish for grammatical reasons. Disney corrected this by calling him "pan Sówa" (Mr. Owl).
In the Italian translation of the Harry Potter books, the male phoenix Fawkes becomes female, and is named Fanny. Possibly due to the fact - just like the examples above - that in Italian "phoenix" is a feminine word.
Following that pattern is the March Hare in Alice's Adventures in Wonderland, who is female in the Spanish version of the novel. A lot of times, when a language does not have gender-neutral pronouns, an animal will be referred to as a "he" or "she" depending on the "gender" of the word of the species if gender is unknown or does not matter.
There is an infamous Polish translation of Winnie the Pooh (called "Fredzia Phi-Phi") which changes Winnie to a girl, since the translator assumed "Winnie" was a shortened form of "Winnifred". (Technically, the bear that gave Christopher's toy bear its name was female, but her name was a shortened form of... "Winnipeg", and Pooh himself is clearly referred to as male in the books.)
Once they started bringing the new suits in along with the new zords, they would repeat this trick whenever necessary. Lost Galaxy, Lightspeed Rescue, Time Force and Wild Force were all adapted from "Pink is the only female Ranger" Sentais, giving the male yellow rangers female counterparts each time. The only occasions where the Smurfette Principle is in effect are Ninja Storm, Dino Thunder and Jungle Fury, all three series featuring Three Plus Two (plus one more in Ninja Storm's case) configurations with female yellows or blues in the source material.
Avalokitesvara, the (male) Bodhisattva of compassion. He is known as the female Guanyin in China and Kannon in Japan.
In the classic Chinese novel Journey to the West, possibly as lampshade hanging, Guanyin is female but often takes male form when visiting the mortal world so that the ignorant are less likely to bother her.
So in the TV series Monkey, Kuan Yin is played by a man with a woman's voice, even in the English dub. It's even lampshaped: 'Kuan Yin? Her with the five-o-clock shadow?'
Actually, looks the Bodhisattva Guanyin has ambiguous gender at least in China (also, see the statues in Buddhist temples in China).
And in the manga/anime Saiyuki ze's out-and-out intersexed, with a No Fourth Wall moment mentioning that they can't actually visibly prove this without raising the manga's rating.
In the Norwegian translation of Peanuts, Woodstock is a girl named Fredrikke (a female name over there).
In a (sort of) in-universe example, the first description of the Ravenloft domain of Kalidnay depicted the darklord Thakok-An as male and the domain's god/ruler Kalid-Ma as female. (Presumably the name "Kalid-Ma" had implied a female gender.) Then the Ravenloft design team realized that the Dark Sun setting's histories portrayed Kalid-Ma as male, meaning they'd used this trope by accident while importing that character to the Land of Mists. A later update to the Ravenloft rules reversed these two characters' genders so they'd conform with Dark Sun.
In the stage version of Richard Powell's novel Don Quixote, U.S.A. rebel leader El Gavilan's very male second-in-command Eduardo was replaced by a female version.
In the Super Mario Bros. franchise Birdo is... confusing. In Japan, Birdo was a male crossdresser named "Catherine". The US manual description says "He thinks he is a girl and he spits eggs from his mouth. He'd rather be called 'Birdetta'." (The last tidbit was ultimately removed). This gave gamers the impression that Birdo was in fact transsexual, an impression that has stuck ever since (in fact, the European Super Mario Strikers website still refers to Birdo as male.)
Apparently no one's told the writers of Nintendo Power about the company's official position... From issue #250 (January 2010)
At once a male crossdresser and a female love interest for Yoshi, Birdo is an enigma, and determining his/her gender is one of life's biggest questions. Then there's the fact that Birdo shoots eggs out of his/her mouth...hole...thing.
And then you get the somewhat subtle subtext in the Popple/Birdo partnership in Superstar Saga. Was he trying to get rid of Birdo because she was too clingy, or...
In the extremely strange Nintendo game Captain Rainbow, 'Catherine' is quite clearly transsexual, and gives you quests to help her prove to prospective male dates that she's a girl including finding her missing vibrator.
This is possibly confused by the fact that Birdo's voice clips in Super Mario Advance were recorded by a female voice actor. And that the green Birdo sounds like a drag queen.
In the Japanese version of Paper Mario: The Thousand-Year Door Vivian is implied to be an effeminate male if not outright transgender. The English version simply identifies Vivian as female.
The localization team got a bit confused in the first Paper Mario game when Watt showed up. In Japan Watt is officially female, but as a sentient ball of electricity with a pacifier who uses her own name as a pronoun (it's implied she's too young to have learned any yet), there aren't many identifying cues. Your only clue is that on her profile she uses a lisped version of "atashi", a feminine pronoun. The English version... sort of flip-flops. Most of the time Watt is referred to as "she" and "her", but other times as "he" and "him". By the time Super Paper Mario came out, the team had apparently settled on referring to him/her as male.
In the Japanese version of Mega Man Battle Network 3, secret boss Serenade is said to be a man that looks like a young girl. The gender is ambiguous in the US version.
The Word of God confirms that Serenade is a sort of perfected being without a sex.
In the Megaman NT Warrior manga, Serenade is referred to both as "he" and "she".
Technically, as a computer program, Serenade wouldn't have a gender.
Wild ARMs 2's Caina was originally a boy. However, since he also happened to have a huge crush on Vinsfeld, he had a sex change during the localization.
Amusing is how the Strategy Guide just alternates using "he" and "she" when referring to Caina.
In the original Bloody Roar, the fighter Fox is a rather masculine woman or a rather feminine man, depending on which side of the Atlantic you're playing on. Fox is male in Japan, remains male in the US release, but becomes female in Europe.
The fact that Fox has a very feminine voice does not help his case.
Fire Emblem: out of the Eight Heroes mentioned in Sword of Seals and Blazing Blade, two are originally female. Archer Hanon, founder of Sacae, gets turned into a male by the localization.
And in a bizarre applications of the trope, Fa(e) is turned into a boy on the Spanish translation for no reason. Then again, that translation wasn't very good.
Yuan is definitely a guy in the Japanese version; Yuan has a clearly male voice, and is referred to as being a guy. For the European Dreamcast version of Shenmue II, Yuan was redubbed by a female Japanese voice actor.
In the Sonic the Hedgehog fandom there is an urban legend that Miles "Tails" Prower was originally designed to be a girl or was a girl in the Japanese version of Sonic 2. Though untrue, this has inspired tons of fanfics, doujins and similar material where Tails is female and usually in love with Sonic.
Sally Acorn started as the English version of the tiny squirrel Sonic rescued in Sonic 1, before becoming a princess Freedom Fighter. But in Japan, the squirrel is male and known as "Ricky".
The German localization of Lufia II: Rise of the Sinistrals sports Artea as a girl. Maybe the translators were put off by the fact that s/he can put on some equipment that was otherwise exclusive to the two actual girls in the party, like most of the staffs in the game or robes or a freaking bunny suit. Or maybe two Action Girls weren't enough for them.
Spinni from Kirby Squeak Squad, who is female in the Japanese manual, but male in translated versions. Also from the Kirby series is Coo the Owl, who is female in Japan, but male in English-speaking countries.
Rumors still persist that Final Fantasy IX's Kuja was originally a woman in Japan and that they changed him to a man for the American version for some reason.
He was dubbed with a male voice in Dissidia: Final Fantasy (both in japanese and in English), so unless that's not being considered a canon affirmation of his gender, he's male.
Let's take her to Thamasa. Also, we never learned Quina's gender, so s/he and Vivi could be the first same-sex marriage in Final Fantasy.
Quina was made female in the Spanish translation of the game (possibly because in Spain, Quina is a feminine name.)
Zidane has a "Protect Girls" ability, which does not cover Quina, though that could always be waved away as Zidane not knowing what to do about Quina.
Made even worse by the fact that Quina can use exactly half of the female-only equipment in the game. Square really didn't want us to know on that one.
The character Harpuia in Mega Man Zero looks feminine and has a female voice actor. No pronoun is used for him in the first English game, so many Western players wondered if he was supposed to be a woman. Capcom USA — unaware that the character would soon become more important — basically said "why not?" They realized their mistake before translating the sequels, but for a while it was actually Word of God that Harpuia was female, and many casual players still think so. (It's grounds for a Gannon-Ban.)
Cubit Foxtar from Zero 3 is also worth mentioning. The Rockman Zero Remastered CD confirmed him as an effeminate male, but the English translation of Mega Man Zero Official Complete Works he is stated to be female. If anything, him really being a man makes more sense in a way, as Kitsune (the fox spirit on which he is based) were often said to take the forms of beautiful women to lure travelers away.
While all classes in Final Fantasy I are supposed to be androgynous, the Spanish translation of Dawn of Souls turned the White Mages into a girls-only class. Okay, so they look particulary feminine, but still..
Not when they go White Wizard and (in the original) sport pecs that rival the Warrior and Black Belt/Monk.
The Russian version of the PC point-and-click game Discworld II turned Death female. Sorta. While the character is consistently referred to and speaks of herself as a female, the character's voice is obviously male (not to mention the translation itself is a voiceover so the original voices are heard in the background). This might have to do with the Russian word for "death" being feminine (see the Bagheera and Owl examples above), but it should be noted that the translated Discworld books properly refer to the character as male.
Chihiro from Bushido Blade 2 is a case: clearly female in the original, but given a male voice actor and always referred to as "he" in the translation.
Poor Noah in Phantasy Star I. Always supposed to be a man (as well as the first incarnation of Lutz, but that's a whole other trope), but the English translation freely flip-flops between using "he" and "she" when referring to him.
For some bizarre reason, the section of the English manual for Ōkami explaining some of the game's more esoteric references tries to claim that the game's version of Amaterasu is genderless. Why the manual does this when characters in the English version of the game constantly refer to Ammy as a female (as she is in the Japanese version and, for that matter, the original mythology) is inexplicable.
Pokemon has example in Pokemon Ruby and Emerald in Magma Admin Tabitha. The small character sprite and the dialogue are rather non-indicative, as well as the character's unisex Japanese name Homura. In actual fact, Tabitha is a man. Not helped by the fact that Team Magma and Aqua both have one male and one female Admin in the games, with Matt and Shelley for Aqua and Courtney and 'Tabitha' for Magma.
The Canadian/American Transformers: Beast Wars has Airazor, who was turned male for the Japanese production from being female. Of course the toy was originally conceived as male too but they made the pre-production decision to add a female to the cast and Airazor looked serviceable. The fact that the Japanese dub was a Gag Dub doesn't help matters. It also turned out more than a little bit weird that Airazor and Tigatron got paired up just before they got fired into space. (Lampshaded with Rattrap Rattle wondering what their deal was immediately afterwards.)
Rusty the diesel in Thomas the Tank Engine ended up being female in the US narration of the 2005 series. Hit Entertainment skirted the issue by pointing out Rusty's gender had never been stated - a 1995 article indicates that Rusty was deliberately made gender-neutral, in response to the common complaints of gender bias on the show and its source material. Both The Railway Series books and the UK narration of Series 9 referred to Rusty as male, and the US narration was later re-recorded (and narrator Michael Brandon gave him a noticeably gruffer voice in the next few series).
Similar to the Rusty example above, Azrael in The Smurfs was given female descriptors in the original Spirou stories and Peyo's books. They made Azrael male in the Hanna-Barbera cartoon, but in a bizarre twist, the gender switch was made canon!
Poor Tails is not safe from it in the Mexican dubs of The Adventures of Sonic the Hedgehog and SatAM, which made him female. Possible cause? Episode 65 of AoStH, Sonically Ever After, where in one fairy tale, Tails realizes that he is in a dress (complete with bust and all!) and says in surprise: "I just noticed... I'm a girl!" The translators probably took it the other way, and well...
It didn't help that Tails has a prepubescent voice which made it a little harder to tell.
The fact that 'tail' is a feminine word in Spanish probably has to do. Tails' name in Mexican Spanish is 'Colitas', or 'little tails' in English, which would sound way too girly for a boy.
It does, however, make the lyrics to "Hotel California" even weirder.
Thankfully averted in Spain, where Tails managed to keep his English name (and gender). But he's still voiced by a woman.
The Brazilian dub of Avatar: The Last Airbender dubbed Smellerbee as a boy for most of the episodes... then it came the episode when she was revealed to be a girl, so there goes a replacement of voice actor and plot holes. And by the next episode, the male voice actor returns. Confused? It's normal.
Spanish-language dubs of Garfield and Friends originally referred to Nermal (whom, for some reason, was Dub Name Changed "Telma") as gatita, the word for a female kitten. It was finally changed in the later episodes.
You know "The Ant and theAnteaterAardvark" from the Pink Panther cartoons? For unknown reasons, the anteater became a woman in the German dub. (A woman with a very deep voice, but still unmistakably a woman.)
The anteater is even called "Die Blaue Elise" ("The Blue Elise" as in Beethoven's "Für Elise")
In the Latin American dub of X-Men, Callisto was mistakenly portrayed as a man during her second guest appearance. For her third guest appearance, she was once again voiced by a female voice actress.
In the Mexican dub of Chowder, Ceviche is referred as a girl in the character-introducing episode "The Apprentice Games", anyways is referred as a boy in later episodes. The character design...well...doesn't help.
The main character, a Hermaphrodite in the original French version, was re-written into a very effeminate, touchy-feely boy for the English dub, likely due to being voiced by a man. This went all fine and well, albeit with a little Ho Yaysubtext, until the series hit a cluster of episodes including one that all but confirmed the main character's (current) biological sex as female. Those and later episodes retconned her back into a female, though the already dubbed episodes were not fixed.
She was just plain turned male in the Hindi and Italian dubs, with dialogue altered to explain away dodgy-seeming scenarios. Why? The initial Translator Gender Confusion just stuck.
Essentially every My Little Pony in the first cartoon, except for six or so Stallions who popped up for one episode, were girls. In order to add more gender diversity to the cast certain European countries made certain ponies into boys, typically the ponies with lower voices.
Generally, in every language thet has gender-specific adjectives, stallion toys are referred to with feminine ones.
The Polish dub of My Little Pony: Friendship Is Magic makes both Spitfire (though only in Season 1, thankfully) and Little Strongheart into boys, for no apparent reason other than that They Just Didn't Care. (Granted, they're minor characters, but still...) Owlowicious the owl, on the other hand, is made into a female, perhaps because in Polish "owl" is a noun with a female gender.
Not to mention that Polish translation of Big Macintosh's blind bag description says "She's very gentle". For truth's sake it seems that the Polish translator of the blind bags probably didn't know that ponies are also male, as the same treatment was also given in Noteworthy's, Meadow Song's and Chance-a-Lot's colector cards.
The Hungarian version plays a very, very big role in this regard, as Derpy Hooves and Babs Seed were changed to males.
The Hebrew dub of KaBlam! turned June into a boy, "John". Why? Absolutely no reason at all.
Unless you add vowel points, both would be spelled the same way in Hebrew (this is the English-phonetics "John," obviously, not its original Hebrew Yoḥanan), and "John" is a much more common name. So it's possible someone just saw it in print and made an assumption.
For Bob the Builder, Muck is male in the UK, female in the American dub. Also, Scoop is female in the Swedish and Polish dub.
The German, Polish, Brazilian Portuguese, 1992 Czech and Serbian dubs of The Brave Little Toaster made Lampy into a girl. (In the 1st Version of the Brazilian dub she's a Tomboy and in the German dub she's a Girly Girl, with the Polish version fitting nicely in the middle). Blanky also counts, because 'blanket' is female in some countries.
Also in the Polish, German, and Latin Spanish dubs, the 'Mish-Mosh' (a Joan Rivers parody) is male, and in the Hungarian dub the Hearse in the 'Worthless' segment is female.
In the British children's series, TUGS, the characters of Sunshine, Captain Star, and Little Ditcher were all male. In the American Cut-and-Paste Translation, Salty's Lighthouse, all three of these characters became female.
In some countries, the Grim Reaper is female, especially in Eastern Europe where "death" is a feminine noun in many languages.