History Main / MaleToFemaleUniversalAdaptor

*** The matter is clarified in the Centauri Republic supplement for the Babylon 5 RPG. Centauri women have six vagina-analogues on their backs, each with its own ovary. To get pregnant, all six part-eggs must be fertilized and combine, a process which make genetic defects extremely rare among Centauri. In many ways, they're [[BizzareAlienBiology the least human-ilke]] of the various races. At least the oxygen-breathers.

* SF author John Varley absolutely ''loves'' this trope:
** The Gaia trilogy has the Titanides, an alien species who are sexually compatable with humans because they were deliberately engineered to be sexually compatible with humans.

* Subverted in ''StationeryVoyagers'', in which there is some discussion about which races of Stationeries are compatible with each other and which ones are not. (Pencils are only barely compatible with Gel Pens, and are otherwise not very compatible with anything. They even have difficulty being compatible with each other, so they're a slowly-dying-out race.) Eraser-Man is only compatible with Erasers, and they're functionally extinct. Whiteouts are only compatible with Whiteouts. Gel Pens, Pens, Markers, etc., can interbreed with apparently no problems. Since it's a divine curse that keeps them from all being human, it [[NewPowersAsThePlotDemands follows its]] ''own'' logic. Humans and Mosquatlons [[{{Dhampyre}} can interbreed]], but it's [[WhoWantsToLiveForever not considered good for a Mosquatlon's mental health to outlive your first love by 500 years]]. Aviatets, however, are only compatible with Aviatets.

[[folder:Real Life]]

* One RL aversion is that female Hyenas are natural {{Futanari}} (Chicks with Dicks for the uninitiated). Of course, it's not a ''true'' penis, that's just hyena weirdness.
* Nagas and mermen are often drawn with human penises (makes sense, half of them is human) that are retractable (also makes sense, the other half keeps their genitals inside). Now, whether the penises operate on human arousal (blood fills the erectile tissue and causes erection) or most animals' method (a bone inside the penis operated by muscles) is up to the artist and observer.

In real life, the genitalia of even closely related species often have significant differences, making interbreeding impossible.

** 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 [[I'mAHumanitarian EATING THEM]]. Despite her affections for Stanley, she is still just a plant that might just eat him if they ever tried doing it.

* ''{{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 volcanic eruption. Of course, the Many-Stalked Flower of Delights is a male to female universal adapter, but it's the opposite of this trope.

* One RL aversion is that female Hyenas are natural Futanari's (Chicks with Dicks for the uninitiated).

* Simply glossing over this (very Edwardian, of course) doesn't mean it's not there; ''John Carter of Mars'' and his red Martian princess Dejah Thoris. Would not her biological equipment for laying *eggs* cause at least a bit of a shock for our Earthly hero?

* Simply glossing over this (very Edwardian, of course) doesn't mean it's not there; ''John Carter of Mars'' and his red Martian princess Dejah Thoris. Would not her biological equipment for laying *eggs* cause at least a bit of a shock for our Earthly hero?

In pornographic materials involving non-humans (whether it be [[FurryFandom anthropomorphic beings]], mythological creatures, or aliens), 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 [[strike: for pleasure]] at times other than during a female's fertile period.

** Well, he ''does'' spend much more time detailing the male genetalia, despite his [[HaveIMentionedIAmStraightToday protestations]] to the contrary.

* JayNaylor varies use of this trope. Sometimes male organs are human-like, other times they are anatomically close to the real life animals. Females, however, universally have human-like vaginas.

* In ''GalaxyQuest'' The huamn aliens are actually some sort of squid thing under their holograms. Chen and Laliari don't seem to care.

* One RL aversion is that female Hyenas are natural Funatari's (Chicks with Dicks for the uninitiated).

** G'Kar ([[spoiler:before his [[CharacterDevelopment spiritual transformation]]) 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.

*** A throwaway line about "what are these cramps I'm getting" when [[spoiler: Delenn]] becomes a half-human hybrid implies that her species, at least, has a rather different reproductive system than humans. On the other hand, that could just mean that her species' females don't menstruate...which is true of most mammals here on Earth.

** Also encountered in the original ''[[{{BabylonFive}} Babylon 5]]'' series, which 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 rubber foreheaded aliens, genetically they have nothing in common with us. To the point they have 6 tentacles on the male and 6 vagina 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...
** G'Kar is stated 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.
*** A throwaway line about "what are these cramps I'm getting" when [[spoiler: Delenn]] becomes a half-human hybrid implies that her species, at least, has a rather different reproductive system than humans.

* Averted in ''{{The Order of the Stick}}'' with {{lizardfolks}}, who have [[http://www.giantitp.com/comics/oots0738.html a genital sheath and hemipenes]], like most reptiles. Though this doesn't seem to stop [[http://www.giantitp.com/comics/oots0676.html interspecies prostitution]], at least with the females.

* In ''{{The Order of the Stick}}'', the undead are disgusted by "biophiliacs" and revolted at the thought they could be so perverted.