History Main / MaleToFemaleUniversalAdaptor

In RealLife, the genitalia of even closely related species often have significant differences, making cross-species coupling impossible (except for bestiality in some cases), even if they both follow the "Sword and Sheath" model.

* In ''Videogame/StarfoxAdventures'', [[NubileSavage Krystal]] - [[IntelligentGerbil a humanoid fox from another planet]] - wears a [[{{Stripperific}} very skimpy tribal outfit]] that mostly consists of [[https://vignette.wikia.nocookie.net/starfox/images/9/9f/KrystalAssistTrophyFront.jpg/revision/latest?cb=20180708110504 a bra and an impressively short loincloth]]. Originally, whether or not she actually ''wore'' anything under the loincloth was left [[AmbiguousSituation deliberately ambiguous]], but ''Videogame/SuperSmashBrosUltimate'', confirms that [[VapourWear she wears absolutely nothing under it]]: her pubic area is [[NippleAndDimed shown in explicit detail]], revealing that her [[https://i.imgur.com//OffoMLh.jpg labia]] and [[https://pbs.twimg.com/media/D1NEb5AXcAATaog.jpg pubic hair]] are quite humanlike.

* [[NubileSavage Krystal]] from ''Videogame/StarfoxAdventures'' wears a [[{{Stripperific}} skimpy tribal outfit]] that mostly consists of a [[https://vignette.wikia.nocookie.net/starfox/images/9/9f/KrystalAssistTrophyFront.jpg/revision/latest?cb=20180708110504 bra and a loincloth]]. Originally, whether or not she wore anything under the loincloth was left [[AmbiguousSituation deliberately ambiguous]], but ''Videogame/SuperSmashBrosUltimate'', confirms that [[VapourWear she wears nothing under the loincloth]]: her pubic area is [[NippleAndDimed shown in explicit detail]], revealing that her [[https://i.imgur.com//OffoMLh.jpg labia]] and [[https://pbs.twimg.com/media/D1NEb5AXcAATaog.jpg pubic hair]] are quite humanlike.

** Averted in the ''Series/StarTrekVoyager'' episode "The Disease", when Ensign Harry Kim has a passionate affair with beautiful humanoid alien Tal, then has the following GettingCrapPastTheRadar discussion.

* ''[[ComicBook/XWing Isard's Revenge]]'': This is discussed in regards to Gavin's relationship with Asyr. While he says "the parts line up just fine" it seems they can't have children. Not surprising, given that Bothans appear to have evolved from canines.

* In the ''Series/BabylonFive'' {{spinoff}} ''Series/{{Crusade}}'', Captain Gideon accidentally acquires a data crystal containing Pak'ma'ra/human porn. The ship's doctor walks in and comments that this shouldn't work (the Pak'ma'ra are humanoid, but closer to StarfishAliens than RubberForeheadAliens with tentacles around the mouth and reproduce asexually). Then they [[HeadTiltinglyKinky bend their necks ninety degrees]] with a look of horror on their faces. Gideon remarks that technology is a wonderful thing.

** The series unexpectedly describes Centauri genitalia quite explicitly and as being mostly (if not entirely, barring near-perverse levels of creativity) incompatible with comparable human anatomy. Although looking like they should be just simple RubberForeheadAliens (they look like sharp-toothed humans with strange hairdos), genetically they have nothing in common with us. To the point they have 6 tentacles on the male and 6 vaginas on the female's backs. Their equivalent of kissing is penetration with just 1. Oh and the tentacles are prehensile and Londo gets caught using one to cheat at poker...

'''Tal:''' Neither was I. Our species look so similar... well, at least on the surface.\\

* Hilariously {{conversed}} about in ''Series/TheBigBangTheory'': After the gang speculate on how Amanda and Sarek concieved [[TheSpock Spock]], considering their difference in species, Raj muses on how in ''Franchise/StarTrek'' everybody's private parts seem to be the same: "No alien lady ever told [[TheKirk Captain Kirk]] 'Hey, get your thing out of my nose!'"

Makes the lovers able to consummate an InterspeciesRomance, if humans are involved. Compare NonMammalMammaries. Contrast ExoticEquipment. [[IThoughtItMeant Not to be confused with]] IkeaErotica.

* In ''Series/{{V 2009}}'', it is perfectly possible for a Visitor to have sex with a human, as evidenced by two of the show's interspecial couples. One of them, in fact, results in a HalfHumanHybrid, something the aliens thought impossible given the two race's diverse origins.
* Subverted in ''Series/{{Lexx}}'' with Stanley and Lyekka. Although they would have sex if given the chance, Lyekka is a highly evolved plant and has no genitalia. There's also the issue of Lyekka's entire raison d'etre being to seduce other species by appearing in a form desirable to them for the purpose of [[ImAHumanitarian EATING THEM]]. Despite her affections for Stanley, she is still just a plant that might just eat him if they ever tried doing it.

** D'Argo (a Luxan) had a hybrid son (Jothee) with his Sebacean (augmented human) wife. Jothee also lots of human-like sex with Chiana. Zhann (a blue humanoid plant) at one point states that Luxans 'make excellent lovers', implying the two can have sex, but not necessarily reproduce.

** G'Kar ([[spoiler:before his [[CharacterDevelopment spiritual transformation]]]]) ([[spoiler: and after: remember the removable eye on the wedding night]]) is seen as being also a bit of pervert, being into Human women as well as at least one Centauri female. His species, although looking reptilian, are marsupials, including keeping their young in a pouch. As Na'Toth said in her first appearance, "It is not my place to speculate on how ''anything'' finds its way into your bed..."
*** He also propositions to Lyta, but only in order to re-introduce the telepathic gene into the Narn gene pool, implying that not only is it possible for a human and a Narn to have sex, but that viable offspring may result from it.

* In the ''Series/BabylonFive'' {{spinoff}} ''Series/{{Crusade}}'', Captain Gideon accidentally acquires a data crystal containing Pak'ma'ra/human porn. The ship's doctor walks in and comments that this shouldn't work. (The Pak'ma'ra are humanoid, but closer to StarfishAliens than RubberForeheadAliens with tentacles around the mouth and a hump that is the female of their species) Then they [[HeadTiltinglyKinky bend their necks ninety degrees]] with a look of horror on their faces. Gideon remarks that technology is a wonderful thing.

* Lampshaded in ''Film/StarTrekVITheUndiscoveredCountry'' when Kirk fights an alien in the penal colony. Lying on his back, he kicks the alien in a jointed area in the middle of his legs. The alien immediately keels over groaning. When [=McCoy=] says "It's a good thing he had knees," Martia, [[spoiler:the Chameloid]], says, "That was not his knee. Not everyone carries their genitals in the same place." Cue shocked look on Kirk and [=McCoy=].

* Hilariously averted in Creator/HarryPartridge 's short "Hot Na'vi Sex". Parodying the romance sub-plot Film/{{Avatar}}, Neytiri and Jake (in Na'vi form) are shown just about to have sex. However, Jake is surprised when he is told to use his [[BizarreAlienBiology "ponytail"]]. When Neytiri doesn't seem to understand what a "penis" is, Jake goes on to pull out [[spoiler: what turns out to be a "Soup Drinker", much to Neytiri's annoyance (we even get a full view of it, which is just a [[GagPenis bendy-straw like thing]] coming out of Na'vi!Jake's crotch). Likewise, female Na'vi seem to have an orifice used to play wind instruments where their vaginas should be. Na'vi sex turns out to be, logically enough, intertwining their ponytails.]]

* In ''[[Literature/DreamPark The California Voodoo Game]]'', two conspirators meet at a sleazy hotel called the Mate & Switch. Each room is equipped with sensory-simulation bodysuits that let the wearer experience the sensations of being the opposite gender, making each a '''literal''' MaleToFemaleUniversalAdaptor.

** Asari do not appear to have this problem, mostly because nothing needs to be, ahem, inserted. All you need is a nervous system and they can initiate melding at a touch, although this doesn't stop them from engaging in physical intercourse.

* ''{{Exalted}}'' averted this trope with an April Fools sex supplement. One of the artifacts in the PDF is called the Many-Stalked Flower of Delights, which allows beings of incredibly different physiology to enjoy the pleasures of each other's company. The creator of the artifact was an Eclipse who apparently '''fell in love with a mountain'''. Not the god of the mountain, the mountain itself. The first use of the item caused a [[SomethingElseAlsoRises volcanic eruption]]. Of course, the Many-Stalked Flower of Delights is a Male-to-Female Universal Adaptor, but it's the opposite of this trope.

* ''XXXenophile'' switches between this and ExoticEquipment.

** Implied in the ''Series/StarTrekVoyager'' episode "The Disease", when Ensign Harry Kim has a passionate affair with beautiful humanoid alien Tal.

* In ''Literature/{{Spellsinger}}'' by Creator/AlanDeanFoster looks like all [[PettingZooPeople sentient mammals]] including humans are compatible, if not able to crossbreed. Jon-Tom [[{{Squick}} decides not to investigate any further]], when he gets a chance.
** In another novel, ''{{Literature/Quozl}}'', the eponymous aliens are human-sized marsupial rabbits, who copulate for recreation 20-60 times a day.[[note]]Which isn't as much as you'd expect. In a time for a human "quickie" Quozl can do it more than a dozen times.[[/note]] For some reason their scientists are shocked to learn they are compatible with humans and decide to keep it a secret from the rest of the population. (Preventing humans from going OutWithABang probably wasn't the reason. [[spoiler:And it didn't happen when the truth was revealed.]] More likely it was done to prevent Quozl from experimenting and to stay hidden.)

** Don't forget the other races; heck, Mordin has ''pamphlets'' on cross-species intercourse for whatever RomanceSidequest you pursue. Drell, Turian, Quarian, he's got you covered. It's not made clear if all the parts line up precisely. The pamphlets are necessary to achieve proper positioning and to hit the right erogenous zones. All we really know is that the respective parts are in the same general area on the humanoid species. It's also for health safety. Quarians with their atrophied immune system are only an extreme case. There are also all kinds of allergies to the body chemistries of other species. There can also be mechanical issues. One pairing (Female Shepard and Garrus, a Turian) has ''chafing'' as a specific risk.

* ''The Elven Bride'' has acquiring one of these as a main plot point, as Elves and humans have some...mechanical issues. Let's just say this work isn't safe for work.
* Subverted in the short ''Little Wife'' where a newlywed couple (both humans) have direct problems due to... size issues. It's {{NSFW}} naturally.

** In another novel, ''Quozl'', the eponymous aliens are human-sized marsupial rabbit-squirrels, who copulate for recreation 20-60 times a day.[[note]]Which isn't as much as you'd expect. In a time for a human "quickie" Quozl can do it more than a dozen times.[[/note]] For some reason their scientists are shocked to learn they are compatible with humans and decide to keep it a secret from the rest of the population. (Preventing humans from going OutWithABang probably wasn't the reason. [[spoiler:And it didn't happen when the truth was revealed.]] More likely it was done to prevent Quozl from experimenting and to stay hidden.)

* Subverted in the original miniseries ''Series/{{V}}'', in which a reptilian humanoid is required to undergo surgical alteration (and make no mistake, even the simple act of implying as much was pretty racy for primetime in 1982!) before mating with a human female. The novelization goes a little further than the TV show did, noting that the human subject of the experiment -- although unaware of ''how'' alien her lover is -- senses that something is ''wrong''.

In works involving non-humans (whether it be [[UsefulNotes/FurryFandom anthropomorphic beings]], mythological creatures, or aliens) having sex, there's a tendency for everything to still use a human-style sexual system (most visible in the penises). Everything will have sex organs based around humans of a size that allows the owners to copulate with each other as the {{plot}} demands. Often, this manifests itself as a differently-colored human penis/vagina, but even when some design consideration is given towards making them look more like the species the creature is based on, they still have a tendency towards human proportions. And human stimulation—it's believed that primates and dolphins are the only creatures that copulate when not fertile.

In works involving non-humans (whether it be [[UsefulNotes/FurryFandom anthropomorphic beings]], mythological creatures, or aliens) having sex, there's a tendency for everything to still use a human style sexual system (most visible in the penises). Everything will have sex organs based around humans of a size that allows the owners to copulate with each other as the {{plot}} demands. Often, this manifests itself as a differently colored human penis/vagina, but even when some design consideration is given towards making them look more like the species the creature is based on, they still have a tendency towards human proportions. And human stimulation—it's believed that primates and dolphins are the only creatures that copulate when not fertile.

* The title trio of the American animated series ''WesternAnimation/AquaTeenHungerForce'' have all displayed sexual interest in and claim to have had sex with human females at one point or another, despite the apparent lack of genitalia (and the fact that all three are a giant, anthropomorphic foods -- a box of fries, a milkshake and a meatball, respectively). And yet two have vaguely phallic appendages and the third can change his form a bit... However, it should be noted that Shake is a huge goddamn liar, and Frylock mentions at several points that Shake doesn't have a penis. When Shake claims to have had sex one time, Frylock's response is "When? How? With ''what''?" It's repeatedly mentioned that Frylock is a virgin, but this seems to be attributed more to his nerdiness than any physiological shortcomings. Finally, any claims Meatwad makes are probably made without any understanding of what he's talking about, just parroting things he overheard from Shake, Frylock, or Carl.

* Subverted in the 1980s miniseries ''Series/{{V}}'', in which a reptilian humanoid is required to undergo surgical alteration (and make no mistake, even the simple act of implying as much was pretty racy for early 1980s primetime!) before mating with a human female. The novelization goes a little further than the TV show did, noting that the human subject of the experiment -- although unaware of ''how'' alien her lover is -- senses that something is ''wrong''.