One-Gender Race



Not a tribe, but an entire race or group of humanoids inexplicably made up of one sex. Male is usually the default, but females under the Cute Monster Girl rules are becoming more common and more obvious. The lack of the other sex is handwaved briefly; Disaster wiping out the other half, or voluntary separation are two common reasons, although sometimes it seems they just don't appear.

If the genetic stock is replenished by mingling with other 'races', you often get the strange explanation that Gender Equals Breed, rather than the offspring being actual hybrids; alternately you can get Bizarre Sexual Dimorphism where two One-Gender Races are revealed to be the male and female versions of the same species.

This is really more about creating a unique culture without having to create an enormous amount of back story. For obvious reasons this used to be an easy device to soapbox gender issues, with all the associated political and social biases in place. Sufficiently old mythological legends may be grandfathered in even in a series avoiding One Gender Races, because the alternative gender is rarely depicted or has no instantly recognizable version.

Tends to be on the High Fantasy of fantastical scale for reasons obvious to anyone with any concept of biology. Assuming sex is genetically determined in the usual way, sex ratios in animals tend to even out over time, even though sexual selection would suggest only a handful of males (traditionally the "unlimited", low-investment sex, at least among mammals—birds, for example, are often a totally different story) are actually needed or prefered for a population. Within a population or an explicitly social group, however, sex may or may not play much of a role. For example, the slightly outdated concept of mammals who have "harems" has been commonly reinterpreted as females tolerating a single male simply due to access to resources his leadership provides, while having more than one is simply bothersome to the group after a certain age. However this doesn't mean 'fewer' males contribute to the species; many are simply forced into being loners, bachelor groups, or "sneakies" who, while 'suboptimal', take what they can get.

In the right (or wrong) subculture, expect Fanon concerning hermaphroditism and various methods of Homosexual Reproduction, especially if the race is all-female.

See also Mono-Gender Monsters, Gendercide, and One-Gender School.

Anime and Manga

 * The Namekians of Dragon Ball. As described by Akira Toriyama, Namekians are designed after slugs, and in-show they reproduce asexually. That said, their secondary sexual characteristics are distinctly male (see the fellow in the moustache in the picture above).
 * Angels in Neon Genesis Evangelion are strongly implied to be hermaphrodites: the genome analyses shows that they have 24 chromosome pairs, which includes both Y and X sex chromosomes (meaning they have the karyotype XXYY). and that the very existence of paired Y chromosomes generates a bit of Fridge Logic.
 * Fairies in Maze Megaburst Space are all female, and reproduce with human men on the one day when they're human-sized.
 * The Solnoids from Gall Force were all female, and reproduced by cloning. Their enemies, the Palenoids / Paranoids, were androgynous but ostensibly male (as far as the viewer can tell; they look more like living suits of armor, but all the voices are male).
 * In the Saber Marionette series, the human inhabitants of Terra II were all male, cloned descendants of the six male survivors of the colonization mission. The Marionettes were a 'race' of Robot Girls that served as Replacement Goldfish because they were not apparently able to create females (having an X-chromosomes apparently didn't help), though their owners tended to have an ironically non-sexual attitude towards them.
 * The Taraks (males) and the Mejare (females) from Vandread; both races (Humans that were deliberately separated by gender) reproduced by couples mixing DNA to create Designer Babies.
 * The Zentradi in Super Dimension Fortress Macross (and the first part of Robotech) segregate themselves into single-sex units and reproduce by cloning, and in The Movie, they're even at war with one another.
 * All mermaids in Mermaid Melody Pichi Pichi Pitch are female. They can reproduce the normal way in their human forms with other races (although this is incredibly rare if not anathema, given their strained relations with anyone else; still, Hanon mentions that mermaid nations have a streamlined age of consent, and considering that some of them are straight and nobody sees anything wrong with that...
 * The more usual way is by having their pearl placed in a giant magic shell when they die to create a successor. (Strangely enough, the only time we see this, it creates a six-year-old, both mentally and physically. It is assumed that they stay that way for the next six years and then age normally.) While this results in no net increase of mermaids, it also ends up in a mermaid longer-lived than usual.
 * The Arume in Blue Drop are all female, and reproduce through technical means. They can even impregnate human women, which they find highly attractive, and actively steal from earth men, whether the women like it or not.
 * Notably, they used to be a two-gender race, but their men went extinct, and reproduce using technology similar to cloning (they give the females some of the genes from males to make recombination easier- they're genetic hermaphrodites, albeit not physical ones). They could technically become a regular two-gender-race again if they would only mate with human males, but they like things just the way they are, thankyouverymuch.
 * The Koorime, or ice maidens, from Yu Yu Hakusho. They usually give birth to an identical daughter every 100 years via parthenogenesis; however,.
 * More in the Manga: Pet Shop of Horrors, . Fandom makes it a business of figuring out how they truly do it...
 * The Alpha Cygnans in Project A-ko are all female.
 * The titular Sekirei are overwhelmingly female (only 2 male ones have been seen so far, 3 if you count Homura).
 * The Mazone in Captain Harlock.
 * It's revealed late into The World God Only Knows that the New Devils who inhabit Hell in the present day are all female.
 * The Kuja in One Piece may be this. It's not known for sure if they are merely a tribe on an isolated island, or if they are a race separate from regular humans. What makes them weird is that they do not have one-gendered reproduction, and they have to leave their island to get pregnant with a man. The child will then always turn out to be a girl. Furthermore, they seem to be better than other people to awaken and train their Haki, but appearance-wise they are similar to other human females.

Comic Books

 * While this is not true in all Transformers comics, some (especially those written by Simon Furman) display the Transformer race as free of gender, with the only "females" being failed alterations or side projects. While this makes sense as they are sexless robots, it's noteworthy that they all look and act "male". Being as the fandom is male-directed, I think we can guess why.
 * The Amazons in Wonder Woman avoided the question by making their race immortal.
 * In the original versions, the Amazons were an all-female society, but still human (they just don't age on Paradise Island). Post-Crisis, this was changed to being a race created by the Greek goddesses out of clay (with the souls of murdered human women.)
 * The Guardians of the Universe in Green Lantern comics were all male, because the females of their race thought the whole "guardians of the universe" project was misguided, and took themselves off to found an all-female society somewhere else. (They were Sufficiently Advanced Aliens, and practically immortal, so the continuation of their race was not a consideration.) When they died and were resurrected by Kyle Rayner, he intentionally made half of them female, to give them back that perspective(it didn't really work).
 * The fairy-like Preservers in Wendy & Richard Pini's comic book series Elf Quest are neither male nor female. Surprisingly, all the characters who encounter any given Preserver seem to know automatically use the gender-neutral "it". The one known exception is from futuristic series The Rebels which has an apparently female elf-sized Preserver named Rosie, who has some percentage of human DNA because the Preserver DNA was not complete enough to clone a real Preserver.
 * Nearly every mammal species on Earth becomes a One-Gender Race in Y: The Last Man, after a strange event somehow kills off every male mammal on Earth except two, a human and a monkey. (The "on Earth" part becomes important later, as )
 * In a story written by Alan Moore, a female alien anthropologist discovers another alien race composed entirely of males, with a tribal culture. When she describes the fact that it's possible to procreate with a female like her, the young man who acts as her translator is eager to try it (and she's fairly receptive, too). Unfortunately, the way the beings of this species procreate is by stabbing a giant snail-like creature in a special purple membrane, which causes babies of the tribe's species to bud off the snail (and also increases the numbers of the snails). The young man then brags to one of his elders that he's finally become strong enough to perform the ritual, the proof being outside his hut: a spear covered in red gore, as opposed to the purplish ichor of the snails.
 * Leprechauns in Wormwood Gentleman Corpse are all male. We aren't given details on how they reproduce.

Fan Works

 * In The Return Succubae are all female regardless of what gender they were as a human.
 * In some Harry Potter fanfiction, Veela are a singe-gender race who reproduce with human men. Depending on the story, male children are human, or there are never male offspring from such a union.

Film

 * The Draks from the movie Enemy Mine are masculine ("I... am not... a woman!"), but reproduce asexually. The Barry B. Longyear books on which the movie was based stated that yes, Draks could have more than one child in their lifetime. The books also confirmed that Draks don't always reproduce asexually. And that falling in love could result in pregnancy all on its own.
 * Memorably subverted with the male ladybug, Francis, in A Bug's Life.
 * Closely related to this trope: pretty much all the Immortals shown in the Highlander movie (notice that there is only one) are male. One theory is that since an Immortal must suffer a violent death to become... well, immortal, and that in past times women were less likely to suffer violent deaths, there would be fewer female Immortals. At the same time, women were less likely to have sword training at the time of their death, and would find themselves more likely to lose a duel, even discounting any physical disadvantage. There are a number of female Immortals on the TV show, most of whom are skilled, tough and clever enough to have at least survived a few duels.
 * A Garry Shandling vehicle named What Planet Are YOU From?, starring the comedian as a member of an all-male alien race sent to Earth to procure a mate.
 * The Hutts of Star Wars are hermaphroditic, but as a cultural thing, they alternate gender terminology between the periods when they are capable of reproduction and when they are not.
 * Boogymen in the Disney Channel movie, Don't Look Under The Bed. This is reveled at the end when the Boogeyman
 * While not exactly a single race or species, dinosaurs in Jurassic Park are all female to prevent uncontrolled reproduction.
 * Possibly the Frost Giants from the movie version of Thor. We only see the males but we do know that their king had a son with no indication of a mother.

Literature
"Niko: "You breed with yourself, goat. I believe you have the corner on inbreeding." Hobgoblin: "Who else would be worthy?""
 * In Piers Anthony's Xanth novels: All-male satyrs mate with all-female dryads, and all-male fauns mate with all-female nymphs.
 * Several examples in the Women of the Otherworld series. Witches are always female, and sorcerers always male, and both reproduce with humans. These are explicitly stated not to be male and female version of the same race. The werewolf gene only passes down to sons. Werewolves reproduce with human women, but their daughters are human. Lycanthropy can be caught via infection/attack, though until recently the werewolves thought no woman could survive the Change. An infected werewolf will pass the trait down to his sons. At the end of Broken,
 * Lois McMaster Bujold has a male one of these in Ethan of Athos, where Designer Babies are created from a bank of ovarian tissue from the initial settlement of the colony. Several generations later, the plot culminates in a representative (Ethan) leaving the planet for the first time, meeting women and the awkward diplomatic question, "Would you care to donate an ovary to Athos?"
 * Jack Chalker's Well World novels (specifically "Quest for the Well of Souls") include, among 779 alien species (not counting inorganic life), the Yaxa, a race of giant scary butterflies of whom only females are sentient. (This helped make up for the presence of a different insect species in the first book which were severely patriarchal. Oh, and there are also the plant-people of Czill, who are completely genderless and reproduce by budding. He likes to play with these issues a lot.)
 * In Storm Constantine's Wraeththu novels, the eponymous post-humans are hermaphrodites who appear male. In the first few books, they reproduce by transforming human males into Wraeththu via blood transfusion, then having sexual intercourse with the "initiate" to set the change. Like many other One Gender Races, the Wraeththu have a female (or, in this case, feminine hermaphrodite) counterpart; and, like many other One Gender Races, the two species don't get along very well.
 * Joan Slonczewski's A Door Into Ocean is about an all female race on an ocean world Shora who reproduce by parthenogenesis. They are master genetic engineers.
 * In Marion Zimmer Bradley's Fantasy Magazine, there's a story about a race of women who reproduce by parthenogenesis. They can interbreed with male humans, losing their "family quirk", and they think of themselves as humans. Or at least they did until
 * Roald Dahl does it twice. In The BFG all Giants are male, the BFG explains that giants simply come into being. Conversely in The Witches all Witches are female (though they don't interbreed with humans and are all evil), but as they are demons and not humans, it doesn't particularly matter. That book also mentions barghests and ghouls to be all-male.
 * David Eddings' Belgariad has an all-female dryad race, who reproduce with human males and produce dryad daughters. Ce'Nedra has a dryad mother and is therefore a dryad, though this is played down publicly (Belgarath at one point remarks that they had enough trouble getting the Alorns to accept a Tolnedran princess without mentioning that she was non-human as well). Dryads reproduce by mating with lonely male travellers. From the fact that Ce'Nedra's family the Borunes descend from a human-dryad marriage, it is clear that dryads can have sons. It is specifically mentioned that many Borune women are dryads and that any attempt to harm the dryad forest would result in them abandoning their husbands and sons. Since dryads live as long as their trees, many of those Borune dryads are likely still around.
 * The Carpathians (a "pre-vampire" species) in Christine Feehan's series of the same name have very few females, mostly due to them not being born very often, or not managing to survive the transition between drinking mother's milk and drinking blood. This leads to male Carpathians either fighting it out for the few females, or finding telepathic human females to mate with.
 * Herland by Charlotte Perkins Gilman sort of fits this trope, as the inhabitants of Herland are perfectly normal human women but can somehow reproduce asexually.
 * In the Discworld series, this is taken to the point where there is no obvious physical difference between male and female Dwarfs; for example, dwarfs of both sexes tend to have long beards. Socially-speaking, there is no issue of gender in Dwarf society, and all dwarfs are treated the same. However, this has the added side-effect of making even talking about a dwarf's individual sex obscene, and female dwarfs are forced to remain closeted as males. This leads to an interesting situation where female dwarfs begin campaigning to be treated differently. Openly admitting to being female, wearing a skirt, or even using female pronouns is subversive, but not even the most radical of them would dream of losing the iron helmets or shaving their beards.
 * Even dwarfs can't tell the difference; dwarfish courtship mainly involves finding out, very tactfully, what sex the other dwarf is; once they're married, it's just sort of assumed the married dwarfs know which is which (or even if they are different sexes). Even pregnancy isn't obvious, probably due to the many layers of leather and chainmail that all dwarfs wear.
 * The witches in Philip Pullman's trilogy, His Dark Materials constitute a separate, entirely female species. They breed with human men, but generally don't get too emotionally attached, since—compared to the witches—humans have such very, very short lifespans. The children of these witch/human couplings might be male or female, but only the daughters are the same species as the mothers, the sons are short-lived humans like the fathers. Witches from some other worlds had men amongst their ranks, although neither male nor female witch lived any longer than humans.
 * The quintessential example of this is The Left Hand of Darkness by Ursula K. Le Guin, winner of both the Hugo and Nebula Awards. The inhabitants of the planet Winter are humans that have been genetically engineered to spend most of their time in an androgynous, sexless form, with monthly periods of "kemmer" in which they develop sexual dimorphism (any individual can manifest either sex) and interest in intercourse. The alien impact this has on a biologically male outside observer is a major part of the plot.
 * Chelonians, in Doctor Who Expanded Universe novels by Gareth Roberts, are a race of hermaphroditic humanoid cyborg turtles. They all self-identify as male, but parents and offspring are referred to as "mothers" and "daughters."
 * Chief Engineer Burgoyne 172 in the Star Trek: New Frontier novels is a member of a hermaphroditic race called the Hermat. S/he dismisses comparisions to the J'Naii by explaining "They are neither. We are both."
 * Perdido Street Station and other Bas-Lag works feature the khepri, an insectoid race who appear to be solely female. That's because the males are barely-sentient grubs who are kept around by the females for breeding purposes.
 * The Clayr of Garth Nix's Old Kingdom trilogy are mostly female. Male Clayr are mentioned in terms of their scarcity, but we never meet any. Children are typically fathered by casual lovers chosen from among the visitors to the Clayr's Glacier.
 * Part of Joanna Russ's novel The Female Man is set on "Whileaway", an utopian alternate future Earth where the entire male population was killed off by a plague generations earlier, though it's implied in a couple places that the men may have in fact been killed off by the women in a world wide war of the sexes. She explores what the ramifications of a single-sex society might actually be (well, when she's not in the middle of an Author Filibuster about how women are oppressed): on Whileaway, for instance, the greatest sexual taboo is cross-generation, getting involved with someone old enough to be your parent or your child.
 * A male example is used in the Cordwainer Smith story The Crime and Glory of Commander Suzal - they were created because all the females were dying out. Oh, and they reproduce... the normal way.
 * The Lyranians in E. E. "Doc" Smith's Lensman series have males for reproduction but they never appear and are described as short, stupid, and useful for only one thing.
 * In Rob Thurman's books featuring the Leandros brothers, pucks are a male-only species. They boink pretty much Anything That Moves, but how they reproduce is left a mystery.
 * Since all pucks look identical, it's been implied that this is some kind of magical cloning (one character remarks that pucks "only consider [themselves] worth reproducing with".
 * Note that Hobgoblin's comment was a response to an insult from Niko.

""No Man nor Elf has ever seen a beardless Dwarf unless he were shaven in mockery, and would then be more like to die of shame than of many other hurts that to us would seem more deadly. For the Naugrim have beards from the beginning of their lives, male and female alike." - from The History of Middle-earth Vol XI, The War of the Jewels"
 * In Trick of the Light, which takes place in the same universe, the main character notes that pucks are a clone species. How they reproduce is never stated, but in Nightlife Darkling refers to Robin as a "Mitotic shithead." Also, pucks are referred to in several places as goats, or mutated goats, or something else about goats. Which leads one to wonder about the origin of the puck species...
 * The process is elaborated upon in Doubletake. Every thousand years or so all the Pucks meet up, count how many remain and generally catch up before, naturally, engaging in an orgy with the only creatures not terrified of that many Pucks in one place. They then choose a number of Pucks by lot and order them to reproduce, which consists of somehow generating a clone completely identical to themselves, including all memory and experience. The cloning is strictly mandated, a death sentence the alternative.
 * In the novella Houston, Houston, Do You Read?,  It was Tiptree, what do you want?
 * Dwarves/Black Elves were originally described as spawning from stone. JRR Tolkien eventually put a much-copied twist on this. Only about one female is born to every three males, and to untrained eyes, their women look very similar to men. They also dress in such a manner to add to the confusion.

"Gimli: It's true you don't see many dwarf women. And in fact, they are so alike in voice and appearance, that they are often mistaken for dwarf men. Aragorn: [whispering] It's the beards. Gimli: ...and this has lead to the belief that there are no dwarf women, and that dwarves just spring up out of holes in the ground! Which is, of course, ridiculous."
 * Lampshaded in the movie:


 * The surviving long-lived ents in The Lord of the Rings are all male, due to a complicated estrangement causing the "Entwives" to wander away thousands of years ago (symbolically, the ents represent untouched wilderness, the entwives cultivated land), never to be seen again. This was probably just because the heroes happened to run into the ents instead of the entwives, since both are supposed to be pretty much impossible to locate under normal circumstances.
 * From Harry Potter:
 * Ambiguous case with the Veela. The Slavic fairies they're based on are all female, and the only full-blooded veela (and, for that matter, the only part-veela) mentioned are female, but it's never explicitly stated.
 * Similarly, all centaurs seen in the books are male. Word of God says that yes, they are a one-gender race.
 * Used painfully (and deconstructed) in The Realms of the Gods by Tamora Pierce. All 'Immortals'--species which cannot die of old age or disease, but can be killed by physical or magical means—are born in the Divine Realms as the product of human dreams or nightmares. One such species, the Tauros, is essentially a race of minotaurs who exist to rape and kill women. Daine, the protagonist of the story, asks the god of the 'duckmoles' (platypuses), if there even are any female Tauroses. When he says no, she gets angry and basically says 'well no wonder they attack human women all the time! That's all they know to do without women of their own who can handle it!' Broadfoot, the duckmole, muses that she's right, and 'Someone should consult the Greater Gods about this...'
 * The Draconians from the Dragonlance novels are all male in the earlier works. This is explained and expanded on in a later book, The Doom Brigade. Very short version, Draconians were a created race, and the creators decided at the last minute not to allow the draconians to breed, and put the eggs containing the female draconians into magical stasis. They were eventually freed.
 * The Hork-Bajir from Animorphs are originally seen this way, the only (externally noticeable) difference being the females have one less facial horn than the males (The free Hork-Bajir who relates this says that there are other differences as well, but refuses to share them).
 * The short story The Matter of Seggri in the collection 'The Birthday of the World' by Ursula K. Le Guin dealt with a planet where males are a rarity, with something like 12 females for every one male. The story subverts this somewhat by being specifically about the anthropological ramifications of having a species like that, and how it affects the planet. It is written like a study.
 * In The Faery Rebels faeries are an all-female race, who leave an egg containing a new faery when they die. Later in the book, it is revealed that
 * In the second book
 * The Arachosians in Cordwainer Smith's short story "The Crime and Glory of Commander Sudzal" are a Lost Colony consisting only of men, as the result of something unexplained about their star which "makes femininity carcinogenic".
 * In the World of Tiers by Philip José Farmer, the all-male Zebrillas are the males for the all-female Dryad. If the offsping is male, he will be a Zebrilla, else, she will be a Dryad. The Zebillas are tall, bipedal gorillas with human intelligence and the Dryads are a whole race of paragons of feminine beauty. The Thoan RPG even had a picture of a mating between a Zebrilla and a Dryad.
 * The Myrddraal in The Wheel of Time are presumed to be this, as they're all male looking (though they're usually referred to as "it" rather than "he", suggesting that they simply don't have a gender). As Myrddraal are a mutant offshoot of Trollocs, they don't have to worry about reproduction—new ones will be born among the Trollocs as a matter of course. Averted with the Trollocs themselves—though none have been confirmed on-page, Word of God is that there are female Trollocs.
 * The Aes Sedai - men and women are born with The Power, but since Saidin was tainted by the Dark One at the end of (and in large part causing the end of) the Age of Legends, male Aes Sedai have been out of fashion - as in, hunted down and Gentled by the Red Ajah, out of fashion. Which makes them suicidally apathetic. Turns out, though, that the practice effectively culled the magic property from humans, in a pseudo-genetic way. Awkward.
 * Justified with the Confessors in Terry Goodkind's Sword of Truth series, since male Confessors don't have the recovery time after using their powers that their female counterparts have, they turn into absolute tyrants.
 * The humans in the Celaeno series by Jane Fletcher are all female, as are (presumably) the domesticated animals. Only the animals indigenous to the planet reproduce naturally, the domesticated animals are cloned, while the humans have their genetic information imprinted from the gene-mother to the birth-mother.
 * In Fletcher's other series, the Lyremouth Chronicles, she solves the issue of dwarf women by making the dwarves hermaphrodites.

Live-Action TV

 * Star Trek: The Next Generation has the J'Naii, a species of androgynous/hermaphroditic beings. However, one identifies far more as female than male, and falls in love with Riker. As she explains, she's always felt more female than male, and is certain there are members of her race who feel the same way, or are more male than female. The ruling J'Naii, however, cannot accept this, and so have her "re-educated". The episode, of course, is a "thinly-veiled" metaphor for acceptance of homosexuality and transgender identities. (Or, at least, it's meant to be.)
 * Tribbles. One sex, seemingly born pregnant, according to Dr. McCoy ("Seems to be a helluva time saver!").
 * The Sontarans on Doctor Who are a militant all male race who reproduce through cloning. According to some of the Expanded Universe material their species originally reproduced normally & was far less war fixated until the day a horredously narcissistic military man, one General Sontar started cloning himself & slaughtered the rest of the population. The canonicity of this is disputed, however.
 * The Drahvins, from the William Hartnell story "Galaxy Four" are a seemingly all-female race. They use the few males only for breeding. Their commanders are naturally born and their footsoldiers are clones.
 * The Carrionites are all female from what we see of them, and can apparently engage in Homosexual Reproduction.
 * The Original Cybermen were all male models. Also, according to Word of God, the original inhabitants of Telos, the Cryons, are an all-female race.
 * The only race on the Dalek's home planet Skaro that definitely has two genders is the Thals. We've never seen a female Kaled.
 * TARDISes apparently. Of course vehicles are female.
 * Ditto the Jem'Hadar on Star Trek: Deep Space Nine, genetically engineered by the Founders to serve as soldiers. Weirdly, though they are also cloned, the Vorta are not single-gender. Probably because the Vorta were adapted from a pre-existing species, while the Jem'Hadar seem to have been created out of whole cloth. Earlier in the series we were introduced to a never again seen Gamma Quadrant species that was awfully similar to the Jem'Hadar, except with more limited versions of their abilities.
 * Word of God states the Tosk were created by the Dominion as a gift to the race that hunts them.
 * On the new Outer Limits series, one of the episodes involved an all female post-apocalyptic society in which almost all males were wiped off the planet due to a scourge virus. They decided to not reintroduce the remaining men into the population because every time they took one out of stasis, it caused conflict in the society because the men pushed limits that the elders were not comfortable with, like building generators or stealing from other towns. Sucks to be male.
 * Babylon 5: All the pak'ma'ra you see are male ... like a Gender Flip of the real life deep sea-angler fish, the female of their species is a limbless symbiote. That, as it turns out, is what the hump that some (but not all) of their species possess is. A pak'ma'ra without a hump should be considered 'single'.
 * The centaurs in Xena: Warrior Princess are all male. They reproduce with human women.
 * The Moclan from The Orville are insistent they are a single-gender race, despite evidence to the contrary.

Oral Tradition, Folklore, Myths and Legends

 * Older Than Feudalism: Greek Mythology has many humanoid beings that appear to be of a single sex, such as female harpies, male satyrs, male centaurs, and female nymphs (which are minor deities that can interbreed with human men). This has inspired many of the other examples on this page. In late Classical works there were female centaurs and satyrs, but these are unusual cases; kentaurides (the female centaurs) were barely spoken of in ancient Greek literature and only one example, Hylonome, is mentioned by name, while the satyresses (the female satyrs) are Canon Immigrants from late 15th/early 16th century poems and art, and didn't exist at all in the ancient works.
 * Originally satyrs were depicted as human men with beards, bald foreheads, pug noses, pointed ears, horses tails, and constant erections. Technically, only the tails and ears set them apart from standard image of a 'wild man'.
 * The original Greek depiction of the very human Amazon civilization variably implied they replenished their numbers the way most warrior cultures did, from invading villages. And depending on how charitable the writer was, any male children were either returned to be reared in those villages, or killed.
 * Most bizarre of all, Hesiod apparently considered humanity to be all male before the gods "cursed" men with the horror of living with women, ruining human society forever. Nope, no misogyny here.
 * With centaurs, it was Depending on the Writer. The poet Philostratus the Elder gave a brief description of "Centaurides" in the story Imagines, and Ovid mentioned one in Metamorphoses named Hylonome, in a passage where she was mourning her mate Cyllarus who had perished at the battle against the Lapiths that occurred after Pirithous' wedding. Shakespeare himself briefly mentioned them in King Lear.

Tabletop Games

 * In the paper-and-pencil RPG Castle Falkenstein, Dwarves are, in fact, exclusively male. They mate with the females of other Faerie-kind; male offspring are Dwarves, while female offspring are the same kind of Fae as their mother.
 * In Dungeons & Dragons:
 * All-male satyrs mate with all-female dryads, and all-male fauns mate with all-female nymphs. The two races are close enough to immortal that it doesn't much matter anyway; both can also mate with humans to create Half Human Hybrids.
 * The all-female race of hags. Hags mate with male humans (and subsequently kill and eat them) to either produce a female hag or a male hagspawn which have almost none of the magical abilities of their mothers, and Hags in Pathfinder give birth to all-female changelings.
 * D&D medusas (based on gorgons) aren't a One-Gender Race; male medusas are called maedars, and are bald humanoids with an affinity for snakes and an intristic stone to flesh ability. They're also extremely rare. In 4th edition, male medusa are just called that, look just like masculine counterparts to the medusa (still bald, though) and have traded the stone-to-flesh-by-touch power for a gaze attack lifted straight from the mythological basilisk. That is, if they look at you, their gaze is so venomous you die of poisoning if you meet their eye. This is the same edition that states there are male harpies, whereas the previous editions meandered between implying that harpies kidnapped human men to breed with and that they laid eggs parthenogenically.
 * There are four species of sphinx; three of which are always male (evil hawk-headed heirocosphinxes, neutral but brutish ram-headed criosphinxes, and good human-headed androsphinxes) and one of which is always female (neutral human-headed gynosphinxes - they're the ones who like riddles). All three male sphinxes can mate with the gynosphinx and have offspring of their own type, but gynosphinxes can only be born of an androsphinx father. For this reason, and the temperament, gynosphinxes prefer androsphinxes.
 * In 2nd Edition AD&D, the standard version of the minotaur was an all-male race. New minotaurs came into being when a human male was cursed to become one by the gods, or when a minotaur abducted and impregnated a human woman. Note that this only applied to the "default" version, and minotaurs from specific game-settings such as Dragonlance did come in two genders. (4th Edition averts the trope altogether.)
 * Nixies in the Mystara setting are an all-female race of water-spirits.
 * The third-party setting Oathbound has aurads, who appear male and reproduce via circle-jerking. (No, really.)
 * In Pathfinder, xills (a Captain Ersatz of A.E. van Vogt's Ixtl) and thriae (inscrutable seers based off of bees) are all female. The Deep One-inspired skum are all male.
 * The Orks in Warhammer 40,000 (and possibly the Orcs in Warhammer Fantasy Battle) seem to be all male, early non-canonical references to female Orks notwithstanding; however, since Wh40k Orks are actually a type of animate fungus that reproduce via spores, attempting to assign a gender to them is basically an exercise in futility.
 * Blood Bowl has orc cheerleaders, which are female. Then again, Blood Bowl is essentially an alternate universe.
 * According to one supplement, the the Gene-Seed—the stuff that makes Space Marines grow to nine-foot tall poison-drinking, car-lifting supermen—is only compatible with male genetics.
 * Transhuman Space features a few Straw Feminist geneticists trying to engineer an all-female human subrace.
 * Xevoz gets hit hard with this one - six races, with two more added later on, and every single member is male, or at least lacking any distinct female traits (one race is Energy Beings after all). Unless you consider that ony the drones in an insect colony are male, and the two character types under the Big Creepy-Crawlies race are heavily implied to be soldiers rather than drones.
 * While not technically a "race" in the usual sense, Eclipse Phase's combat-tailored Fury biomorphs are almost all female, in order to reduce unnecessary aggression.
 * The Lizardmen in Warhammer Fantasy Battle are all males; they are born from spawning pools throughout Lustria, and were initially created by the Old Ones. Their war with the Skaven began when the Skaven poisoned one city's spawning pools.
 * The Medusas of GURPS Banestorm are all female. They mate (carefully) with humans, elves, and orcs' males to produce offspring. The kids are usually medusas, but some are boys with a recessive medusa trait.
 * Word of God says that the world of the Banestorm also has Euryales, a small all-female reptilian race, whose eggs are fertilized by eating their dead; and Sthenos, a much bigger all-female reptilian race, produced by a virus that infects human (or orc or elf) women, and spontaneously transforms them if they are violently injured.
 * In Magic: The Gathering, angels are always female. (There is one exception, but he comes from an Alternate Universe).
 * The card art only shows females (Most Artists Are Male). The art directors once required an artist to redraw a card after he turned in a painting of a male angel. According to the books and text materials, there are plenty of male angels (Serra, at least, made sure of it for her realm).

Video Games

 * Guild Wars contains two races that fit this category as of the Eye of the North expansion: Dwarves and Charr. In the case of the latter, it has been explained why this is the case, and in the case of the former it is lampshaded by one of the dwarf character's random lines.
 * 'How do you know you've never seen a female dwarf? Eh? Eh?'
 * Similarly, the Harpies appear to be this, as all 3 humanoid forms are female, and while never directly explained it's implied the griffins that accompany them could possibly be their males.
 * Dungeon Siege II has the Dryads. Quoted from page 40 of the manual, "These creatures resembled Human females in many ways. (If there are male Dryads, they keep themselves well-hidden. None has ever been seen." Also, "No one knows how they reproduce (any enquiries on the subject are met with hostile silence)".
 * Half Giants are all male, though they can procreate with other races. A quest explains that
 * Mithra and Galka in Final Fantasy XI, where players can create only female and male types, respectively. The Galka reproduce by reincarnation, with it suggesting that the number of Galka in the world is a fixed figure (or decreasing, if being killed before their time prevents reincarnation). Even with no need for sexuality, the Galka still seem to fall in love with females of other races. Among the Mithra, males are rare and as a result, have been forced into protective status (probably not too enviable a position, with them most likely being treated as little more than objects and forced into passionless sex for reproduction only on a constant basis). Doesn't really change that Wings of the Goddess (which takes place during the Crystal War) just ignores this and keeps the mostly female motif present in the modern day (giving us one token male that just seems to exist as Square telling people to stop asking questions about the males at conventions).
 * Later, an all-female enemy race called the Lamia was added to the game, though their status as a One-Gender Race may be justified by the insinuation that they're actually an artificial race used as biological weapons...and because the mythical creatures they're based on are always depicted as female.
 * Also in the Final Fantasy franchise, the various incarnations of Ivalice (aside from the all-human original Final Fantasy Tactics) feature the Gria. Except for humans, most other races are effectively all-male, as well, but it appears simply because they have no alternate gender appearance, and Final Fantasy Tactics A2 has a Luck Stick vendor and exchanger who are described in-game as male and female, respectively, in spite of appearing completely identical. The Seeq have an official female sprite, though it's just a Seeq Viking with a pink outfit and lipstick, and not playable.
 * Officially there are male Viera, though none have appeared in any games. According to canon sources, they live separate from the female half of the species and the two populations only meet when it's babymaking time. A young, spoiled Viera appears in a series of missions in TA2, and wants the player to help her capture a Wyrm so that she can take it home and impress her father. So far, Gria have only appeared in one game of the Ivalice series, and their role was tertiary at best, so no word yet on how their society functions.
 * Tactics A2 plays with your expectations a little, with the Duelhorn Boss, Night Dancer. From first appearances you might think she's the only female Bangaa character and therefore is safe for your Viera unit to hit under the "No Harming Opposite Gender" law. But no, she's a got a pickle surprise.
 * As far as Final Fantasy XIV goes, we haven't seen female Roegadyn or male Miqo'te yet, and it apparently hasn't been decided whether or not they'll appear in-game (although Word of God confirms their existence). And the Highland Hyur have only male adventurers.
 * The Gerudo from The Legend of Zelda are an entirely female race of warrior-thieves. Even though they're apparently human, only one Gerudo male is born every hundred years (the only one known is Ganondorf) and is destined to become king. In fact, the gossip stones found in the game reveal that the Gerudo often visit the town for the purpose of finding a man to borrow in order to make more little Gerudo. There seem to be no Goron women, though this is difficult to tell based on their strange appearance.
 * Gorons all identify as male, referring to each other as "Brother." This could be the case of identity (like Diskworld) or Asexual Reproduction, since all cases of child Gorons seen in the series only have fathers and mothers are never mentioned. The manga of Ocarina of Time has a few female Gorons that are only visibly different due to long eyelashes.
 * In Startopia, all alien species are identical, except the sexy Dahanese Sirens - beautiful humanoids with angel wings whose role on the station is to "love" other beings. They have two models, one purple-haired woman in a racing swimsuit, and one blonde, shirtless man.
 * Of course, the genders only seem like that to us, apparently in the game files they are reversed (i.e. The "woman in a racing swimsuit" is the male of the species)
 * The asari from Mass Effect are a literal one-gender race, who reproduce through parthenogenesis. Of course, they're also among the wisest and most ancient races in the galaxy, powerful users of biotic techniques, and the founders of the Citadel Council, which governs 80% of known space. But the player is likely to be more interested in their ability to 'merge' with anyone, regardless of race and gender. The asari even have a Fantastic Self-Racism against asari who join with other asari. Partly because the race feels that nothing new is gained from merging with other asari, and partly because only "pureblooded" asari can be born with a genetic birth defect that turns them into deadly sex vampires.
 * Valkyria Chronicles (probably) has the titular Valkyria, a Proud Warrior Race actively worshipped by basically everyone. While we only see two living examples in-game, being that the Valkyrur are something of a lost culture, no mention of male Valkyria is ever made. Given that Valkyries of Norse myth, which they're based on, are always female anyway, it's probably a safe assumption that the Valkyria are as well.
 * Possibly the silliest example is Gender Wars, in which humanity has separated along gender lines into two warring factions of exaggerated stereotypes, both of which reproduce through technology, along with stealing required genetic materials from the other side.
 * A number of Pokémon are all-male or all-female (Jynx and Kangaskhan, for example), while others are simply male and female versions of each other (Volbeat/Illumise, Tauros/Miltank, possibly Braviary/Mandibuzz and the Nidoran family), or evolutions that cut across gender lines.
 * And some of them all look like one gender but can actually be either, such as Lopunny or Gardevoir. The latter was later given a male-only counterpart named Gallade; however, Gardevoirs of both genders can still exist. Hell, there can be male Bellossoms and female Mr. Mimes.
 * Breeding a male only creature (We'll say Tauros) with anything (apart from Ditto) will never, ever get you another Tauros. If you breed it with a Ditto, the implication seems to be it became a female bull. Sort of.
 * Dittos are also genderless until they transform. In-Universe, nobody knows the difference between a male and female Pokémon, aside from Gen 4 on, which have a few visible differences (Pikachu with a heart shaped tail, for example). Nobody knows how they make eggs either, but that's going off topic.
 * It becomes ridiculous when you consider legendaries. Presumably the reason Legendaries are Genderless (besides breeding Legendaries being a Game Breaker should it ever happen) is because they're immortal and don't need to breed. But then you get Legendaries like Heatran (male or female) and the Genie Trio (Thunderus, Tornadus and Landorus) who are specific genders confusing the issue.
 * The Dremora from The Elder Scrolls are all men, except for one (randomly generated) Dremora lord from The Elder Scrolls IV: Oblivion. In addition, both the Golden Saints and Dark Seducers of the Expansion Pack have a similar but reversed gender ratio, though there are considerably more male Golden Saints and Dark Seducers than female Dremora. It's proclaimed by an in-game book as justified, saying that Mehrunes Dagon (creator of said Dremora) sees females as inferior in war. No one said the god of war was politically correct, and Dremora are entirely immortal and entirely sterile, technically not even making them a species at all. As they have no interest in sex at all, and may not even be equipped for that in the first place, gender is more of an aesthetic concern, anyway.
 * Zig-Zagged in World of Warcraft. The developers clearly didn't write the races as a One-Gender Race, but looking at the playerbase you'd probably jump to this conclusion. While most player characters were obviously male or female depending on the race (Night elves were mostly female; Trolls were mostly male) and some races were about equal ratio (Humans, gnomes, Undead) but you'd be hard-pressed to find a female dwarf who isn't an NPC! It was even a joke saying that dwarves were a race of "Reverse amazons" on the board for a while in classic. Tauren and Orc women are likewise rare in terms of player characters.
 * When new races were added, things got different. It may be a joke to the common hairstyles of the blood elves but most blood elves appear to be female, especially since they're quite frail looking. (Then again though, the males are actually the most realistically-proportioned character models in the game) Draenei seemed to be well balanced, as do the Goblin and Worgens, although it's not uncommon to see a higher male to female population in the playerbase.
 * Oracles, Murlocs, and Kobolds seem rather one-gendery.... though they maybe don't have any sexual dimorphism at all. Furbolgs are a good example of this. The one female furbolg seen looks exactly like every other furbolg out there.
 * Additionally, several races have both genders according to the lore, but only one (male, with an exception being the succubus) is depicted in game. Ogres, Broken and Lost Ones, for example... although a half-finished female Broken model exists in the game source. Literally half-finished. If the macro system's UnitSex function is to believed, some of the 'all male races' such as Ogres do have female individuals in the game. Apparently the player characters just can't tell the difference.
 * The Warcraft D20 monster manual states explicitly that Harpies reproduce by copulation with raping a captured humanoid race, preferring elves and humans.
 * In Warcraft III 's campaign, the Night Elves begin as a one-gender race, until the male Druids, who have apparently been hibernating for a long, long time, awaken.
 * Even in World of Warcraft, there are many more female Night Elves than male. This is probably a Rule of Sexy choice by Blizzard and the players, and the (Handwaved) reason for this is probably that many males are still trapped within the Emerald Dream. If players are ever allowed to visit the Emerald Dream, one can bet that there will be plenty of female Night Elves running around.
 * In the MMORPG Trickster, Cats, rabbits, foxes, and sheep are female, raccoons, dragons, lions, and bulls (well, duh) are male. Less so than most examples in that all the characters are really humans with costumes consisting of a headband and a tail.
 * In Arcanum: Of Steamworks and Magick Obscura, several of the playable races can only be male. This has an in-game justification of the females of certain races being deliberately sheltered and do not go adventuring. The real reason was technical; there was not enough room on one CD for all the sprites required to have females for all the races.
 * The Kremlings of Donkey Kong Country were like this for a long time, with only males depicted (there is a throwaway reference to a wife for K. Rool in the third game, however). It took them until Donkey Kong Barrel Blast to finally introduce female Kremlings to the series.
 * Only male Grendels and either male (in 2) or female (in 3) Ettins occur without player intervention (or breeding, once you have both genders) in the Creatures games.
 * Neireids in Soul Nomad and The World Eaters are all female, and reproduce with Human (and possibly Sepp, who can breed with humans) males, producing neireid offspring. All the Redflanks that appear in the game are males and all the Sky-people females, but in the case of the Redflanks it's mentioned by Grunzford that the Redflank females died out awhile ago, which is why there are fewer and fewer Redflank as time goes on, as well as why the current population always appears to be older.
 * Darkstalkers: The Catgirls for Fanservice purposes. Or are they....
 * Archers from Disgaea were always female and created by their World Tree until the third game, but the males were referred to as "rangers" instead. Then there are the succubi and catgirls. Since each class is gender-specific, there are duplicate male and female counterparts of most classes. Since the "monster" classes are all gender-specific, as well, but monsters are, through Mediators, capable of marrying and even producing offspring, it's safe to assume that Gender Equals Breed.
 * Every race except Poms in NeoSteam. Even the Humans. Humans are all male, with a female counterpart race in Taxn Humans. Lupine and Tarune are all male, with an all-female counterpart race in the Lyell. Elves are just plain all female, with no male counterpart. They're not actually stated to be all male or all female, but those are the only options available to PCs, and we don't see any NPCs contrary to this pattern, either.
 * You rescue eighty dragons in Spyro the Dragon, but every single one is male and female dragons are never mentioned. Averted in the third game, which features female baby dragons, which means that the female dragons were off laying their eggs in solitude -- Gnasty missed them completely.
 * The Valkyries in Ratchet and Clank are a female only race due to a long emigration from their home planet. It took them hundreds or thousands of years, and all the men were killed for failing to stop and ask for directions.
 * The Kaka clan of BlazBlue are at least close to being a One-Gender Race that reproduce via parthenogenesis. Kaka males are mentioned as being incredibly rare, and none are seen in game.
 * In Monster Girl Quest, all the monsters are female, and survive by raping human males. Early on, we find out that this isn't their fault: The human's goddess has forbidden sexual intercourse with monsters. Again, they're all female, so it's just a slow form of genocide.
 * Parodied with the Dreamboat Kingdom in Xolga and Mr. Toko. For our protagonists, said kingdom is composed exclusively of males, but the Dreamboaters claim that they do have different sexes, is just that their females are Bishounen-looking while their males look muscular but very campy. Not that Xolga is entirely convinced about it.

Web Comics

 * For a very long time, the webcomic Freefall left it apparent that all of the robots (whose enormous population forms a major part of the cast) were considered male by default. Only in strip # 1,403 does the question finally come up. Disappointingly, the explanation is as stereotypical as it is silly: the robots determine themselves to be male or female based on how much talking they do.
 * The Uryuoms in El Goonish Shive don't normally have genders, per se; any two Uryuoms can form an egg together, and they can use DNA from any living species to fertilize it, including Half Human Hybrids of course (surprisingly, they aren't The Virus, being relatively benign and somewhat whimsical). Those living on worlds where gendered species are dominant will generally adapt to the local customs; on Earth, they generally choose their own gender at some point, though some have one chosen for them by their parents.
 * In Angels 2200, the Humans have become (almost) entirely female after a mysterious plague wipes out 99.5% of all males on Earth. The few surviving men are carefully protected to ensure the survival of the species. One of the major questions of the series is whether this affected the colonies as well, as it occurred during a major insurrection (and may have been a caused by a biological weapon).
 * Msfhigh has the Legion, who are a race of Green Skinned Space Babes, who reproduce by converting other races into Legion. They used to be similar to the Borg, but now they act nicely, and retain free will. They're still a bit love-crazy, though.
 * Not So Distant's Albategna (of which the main character Sadachbia is one) are hermaphroditic. In English the pronoun "he" is used to refer to Sadachbia simply as a default, because "it" would be rude and English hasn't used the pronoun "ou" since the 13th century.
 * Schlock Mercenary: Carbo-silicate amorphs are, for all intents and purposes, a One-Gender Race, and their reproduction process is explained in some detail in the comic, but is basically an interesting example of how parthenogenesis could produce offspring which differ from the parent. Technically they don't have a gender at all; Sergeant Schlock is referred to as "he", but Schlock is kind of an odd duck, in that he is A) actually kind of violent, and B) not the result of normal amorph reproduction, but the result of a critical failure in the process of amorph-to-amorph combat.
 * The Elves of Fetch Quest: Saga of the Twelve Artifacts are in danger of becoming this, especially with factors both genetic and historical.
 * Bardsworth: The faeries are all female and the demons all male. New faeries are born by combining magic and a tree
 * Erfworld: Not surprisingly, Charlie's Archons are an all female species. As this world lacks childbirth (or children), and sex appears completely disconnected from procreation, a number of races we've encountered might be all male (or possibly female for some elf variants); we're sure about the archons.
 * If you count unit classifications as racially distinct (this world runs on tabletop strategy physics), there are known all female-vampire subraces, although there are also regular female vampires.
 * The Phoenix A species of Dan and Mab's Furry Adventures is only female, and don't reproduce conventionally since there are always a certain amount of them at any given time, and their method of "reproduction" is to essentially reincarnate.

Web Original

 * Neopets has numerous types of faeries with different elements and alignments, all of which are all female. No explanation is ever given.
 * And apparently if you try to get into the contests or "Neopian Times" (weekly site newspaper) with a story about a male faerie, it will get rejected solely because of that - the staff doesn't seem to want to endorse any mention of male faeries at all.
 * The Fairies of the Notting Cove series are all female.

Western Animation

 * While not a concrete example, female Transformers are exceedingly rare. In fact, in some continuities, they don't exist at all. Why a mechanical race even has genders is a frequently-debated topic, as are... how to put this delicately?... other questions related to gender functions.
 * In the Generation One cartoon, the Transformers were built as civilian and military hardware by the Quintessons for sale to other species. Though the Quints themselves are a One-Gender Race, they know and understand genders and built their products to appeal to their clients. Another thing to note is that for the longest time there were only female Autobots, the civilian line. Female Decepticons (the military line) were unheard of, and we only began seeing female villains in the sequel series Beast Wars (Blackarachnia) and Beast Machines (Strika). Both of whom might not have been Autobots or their descendants: Blackarachnia was a reprogrammed Maximal (Autobot descendant), and Strika is a revived spark, of unknown original side.
 * The idea of Transformers being a genderless race seems to have been thrown for a loop by the new Aligned continuity introduced by Hasbro; in which, one of the Thirteen Original Transformers, Solus Prime, is explicitly revealed to have been female (and thus the first female of their race).
 * Similarly, The Smurfs do have some females... three in fact, but at least two of them weren't "natural" members of their species but rather the results of Gargamel creating golem-like beings to infiltrate the Smurfs, and Papa Smurf subsequently making them "real". Smurfs appear to reproduce by stork.
 * The Pixies from Winx Club are a female-only race. They don't need males since they are created by a magical tree in their village. Amore (the pixie of love) got really sad when this was pointed out to her by Jolly.
 * This is made more confusing by the presence of male pixies in their Spin-Off.
 * We also never see any male fairies...
 * My Little Pony actually made more sense without the "big brother ponies," when the ponies appeared to be a One-Gender Race that reproduces via parthenogenesis, resulting in babies physically identical to their mothers.
 * According to one of the comics, little ponies reproduce by looking in a Magic Mirror and wishing for a baby, hence the identical babies. The real question is, where did the babies without an adult counterpart come from? The "old way," maybe?
 * Not surprisingly, when Lauren Faust (who watched the older cartoons growing up) came on board for My Little Pony: Friendship Is Magic, she promptly made sure to avert this trope - Equestrian ponies come in both genders and reproduce the way Earth horses do, no ifs, ands, or magic mirrors.
 * The Amazonians from Futurama, who ousted their male population under the compulsion of the mysterious Femputer. The other men died from crushed pelvises from Snu-Snu.
 * The rolling stock from Thomas the Tank Engine. Passenger cars such as Annie and Clarabel, Henrietta, and Old Slow Coach are always female, while freight cars such as the Troublesome Trucks, the Spiteful Brakevan, Hector the hopper car, and Rocky the repair crane are always male.
 * Star Wars: Droids: The Adventures of R2-D2 and C-3PO just might have one female droid among the entire cast. The droid is pink, but the series consistently averted the Pink Means Feminine rule. If the droid isn't female, then all robots in this cartoon are male.

Real Life

 * The Teiidae family of whiptail lizards includes many species that are either all-female or nearly so. This is made due to parthenogenesis induced by sexual stimulation. Yep, hot girl on girl action producing babies. How wicked can nature not be?
 * There are also lizard species that require sperm to reproduce, so they seduce men of other species.
 * There are some species of fish, such as the Amazon Molly Fish, that are only female, reproducing solely with the males of another certain species (one which has both males and females). These species work this way because either the act or the presence of sperm will stimulate egg production. Genetically, the offspring are the mother's.
 * There is a species of all male fish (see https://web.archive.org/web/20101018022453/http://eobasileus.blogspot.com/2008/03/male-chauvinist-minnows-form-all-male.html )
 * The wolbachia bacteria (right now confined to arthropods) kills all mature males, turns all other males female and allows females to have virgin births. Many species now have it incorporated into their sex-determination system pretty much permanently.
 * The barramundi is a species of fish where all start as male and slowly change to female throughout their lifecycle (resulting in the vast, vast majority of large fish being female).
 * The clown fish essentially does the opposite. Fish are either sexually immature males, mature males or females with one mature male and one female living in a given population of clown fish. When a female dies, the mature male becomes the female and an immature male becomes the mature male. This means, that buy the time Nemo met his father in Finding Nemo, he would have actually been his mother.
 * Aphids reproduce mainly by parthenogenesis, and they are indeed born pregnant. Some aphids do have males and sexually reproducing females at certain times, such as in the fall so that they can produce eggs that can survive through the winter, but for the most part aphids are a One-Gender Race.
 * While there are female bees and male bees (drones), as a general rule the bees you'll see are female. Only the queen reproduces in a beehive, and she can choose whether to make sterile female workers (diploid), another queen (diploid individuals fed royal jelly for thirty days), or a drone. Drones are haploid, meaning they were not fertilized, and their sole purpose is to mate with the queen to give her a lifetime's supply of sperm. Once they mate, they are cast out of the hive and die or die thanks to their genitals being ripped out of them after intercourse.
 * Mycocepurus smithii, a species of ant, was recently discovered to be entirely female, reproducing asexually.
 * While angler fish have both males and females, the males attach to females and start to bond with them until the male is little more than a lump of flesh on the female.
 * The Desert Grassland Whiptail Lizard, an all-female species. The most commonly accepted explanation for this is that they comitted Gendercide.
 * Some species of rotifers are apparently 100% female, though it's possible that the males (which tend to be a lot smaller) just haven't been seen yet. Even rotifers that are capable of producing male offspring usually do so only if the puddle they're living in starts to freeze or dry up, as mating with males allows them to produce durable eggs that can endure harsh conditions. When conditions are good, rotifer populations go all-female, and the thin-shelled parthenogenetic eggs they lay contain clones of themselves.
 * Bdelloids. They are all female and lay fully fertilized eggs.
 * Subverted with hyenas. Medieval scholars thought spotted hyenas were all male and reproduced homosexually.