Aliens Made Them Do It

"Last time aliens invaded all they did was force the most intelligent of us to pair off and mate continuously... Oh, yes..."

- Professor Hubert Farnsworth, Futurama, applying an Anticipatory Breath Spray.

A specific kind of Applied Phlebotinum often used in Fanfics to get two characters who have little motivation to have sex to do so.

In the most traditional use of this trope, aliens kidnap the characters and require them to have sex for scientific study or experimental purpose. The trope's meaning widened to include any case where an external force contrives, orders or forces the characters to have sex for its own purpose. The trope is parodied as often as used straight.

A Shipping trope. Often used in Slash Fic, or with Crack Pairings of characters who hate each other. May lead to M Preg justified by alien technology.

A variety of Deus Sex Machina, and an extreme case of Kissing Under the Influence. Compare with Mate or Die.

As far as we know this is impossible in Real Life, so No Real Life Examples, Please!

Anime and Manga

 * Outside of fanfic, a tamer example is found in Super Dimension Fortress Macross/Robotech, where the Zentraedi force Misa/Lisa and Hikaru/Rick to kiss. A joke is found in the Robotech Novelization about it: judging by the Zentraedi's response, if they had shown them what sex was, it probably would've ended the war right then.
 * That scene where the Zentraedi abduct the main characters from Super Dimension Fortress Macross and ask "I demand you show me how this 'kiss' process works" gets parodied in a Super Robot Wars Alpha 4koma. Boss and Dr. Hell from Mazinger Z (and Great Mazinger) are amongst the people they kidnapped in the parody.
 * Deconstructed in Blue Drop: Tenshitachi no Bokura, in which the main character must have sex with a certain girl who is actually  in a week or else the evil lesbian aliens will kill them both. Needless to say, neither of them want to have sex, and are in fact disgusted by the idea. It gets worse for them from there.
 * The doujin U.F.O. by Naruko Hanaharu has aliens abducting two humans from Earth shortly before it is destroyed. In the end it turns out to be . It is also worth noting that the only other option for the girl involved was artificial insemination.

Comic Books

 * The American Way: Referenced in John Ridley's comic miniseries -- to take everyone's mind off a recent tragedy, it is suggested that two high profile superheroes go on a high-profile dinner date. When the woman(who is quite forceful) suggests to the man(who has a reporter girlfriend) how they should... well, it's never made clear what she suggested... anyway, the result is the two of them beating the crap out of one another in the sky over the restaurant and refusing to talk to each other ever again. The official explanation, given to the papers by their government liaison the next morning? Aliens Made Them Do It.
 * Johnny the Homicidal Maniac: This is Played for Laughs in one of the "Meanwhiles" when a pair of aliens abduct a store manager and force him to have sex with one of the "females" of his species... which they have apparently taken to be a chicken. After much arguing and threats, he copulates with the chicken and a flash-forward at the end shows him with human-chicken hybrid children, saying "And that's how I met your mother."
 * Binky Brown Meets the Holy Virgin Mary: In Justin Green's classic underground comic, Gary Stu Binky Brown, as a parochial school teenager, imagines that "bad men" have tied him and his latest crush together...they can't help having "impure thoughts" under those circumstances....
 * According to this article from Cracked, this once happened to Superman and Big Barda.
 * Superman himself managed to resist, but Barda apparently made at least one tape before he got there. Thank you, John Byrne.
 * Superman only "managed to resist" to the extent that the director commented that his performance wasn't very enthusiastic. He was in the process of making a porn movie with Barda when her husband showed up to rescue the pair (before they actually did anything, naturally).
 * Mystical forces made do it in the "Twilight" arc of Buffy the Vampire Slayer Season Eight.
 * In New Mutants, when Empath, breaking into Xavier's School, is surprised by Tom and Sharon, he uses his emotion control power to make them have days of uninterrupted, kinky sex instead of giving alert. It's Played for Drama, as they are pretty much written like rape victims afterwards, and any kind of romantic tension which could have existed between them is dead for good.
 * Parodied in a Show Within a Show Slash Fic Empowered reads about her teammates.
 * In an issue of Outsiders, a Russian gangster gets the powers of the demon Sabbac (an Evil Counterpart of Captain Marvel, whose name is an acronym of the names of demons the way "Shazam" is an acronym of the names of gods) which includes control over the Seven Deadly Sins. He attacks a prison and makes all the inmates and guards have an orgy, then makes his lackeys - the four surviving members of the Fearsome Five - have sex with each other. Specifically, he pairs off Psimon and Shimmer, and Jinx and Mammoth, then threatens "Don't complain, or I'll have everyone switch partners. Which means either Mammoth will be banging his sister or you'll all be having the gay sex." When the Outsiders show up to fight him, he threatens to use his lust power on Starfire to "see if the carpet matches the drapes."
 * In a Titans issue, Starfire and Nightwing - who used to be engaged - are searching an abandoned building and decide to have a quickie for old time's sake. Shortly afterward they realize how out of character (or, at least, unprofessional) that was. It all starts to make sense when they realize that the person they were searching for was one of seven demons, each of whom is an incarnation of one of the Seven Deadly Sins. (Ten guesses which sin their target represented)

Fan Fic

 * In the War Craft Fic Ethereum Gladiator, this trope is reconstructed something fierce.
 * Plots revolving around an accidental or forced bond are uncannily common in for the Snape/Harry ship in the Harry Potter fandom. In the canon proper, things like more powerful charms and curses and love potions have similar effects.
 * It doesn't help that  was conceived while his father was under a love potion,  . So, unfortunately...
 * In Batman or, more rarely, other DCU fanfiction, "sex pollen" created by villainess Poison Ivy is used for this trope.
 * DC Nation turned a really bad Poison Ivy/Flash ship into an actual plot point after the muns behind the disaster left. The "Brain Spores" that took over Wally West were a form of sentient plant that Ivy realized too late would have been a perfect mate. It's been used as a motivator for Ivy and a source of headaches for Wally since.
 * Techically a demigod made them do it but in an extremely NSFW fan comic by Sharpie, the ladies can't keep their hands off of Superman.
 * Similarly, 'alien sex pollen' generally tends to show up in Doctor Who fanfiction for a similar purpose. As do fics mocking it for being an overused cliche One editor found this Stargate parody fic subverting the trope to be amusing.
 * Even more delightfully inverted in Abstain, a Stargate Atlantis "aliens make them NOT do it" fic.
 * This Hitch Hikers Guide to The Galaxy fanfic, entitled "Aliens Make Ford and Arthur Have Sex''. It is followed by sequels in which M Preg results, and is justified not so much by alien technology as because it's funny.
 * So common on the Star Trek Kink meme that it has its own tag
 * Nearly happens in the Firefly fic Forward's "Charity" episode, involving . The actual reasoning is complicated: They're protecting a group of refugees, but   In this case,   It is only stopped when.
 * In Ranma One Half fanfic there's the fanonical "passion spice", a Chinese Amazon drug which acts as a super-aphrodisiac.
 * Doctor Who: One Fourth Doctor/Sarah Jane fanfic involved with aliens kidnapping the characters and forcing them to mate, which they in the traditional fashion. Only afterwards did the Doctor point out that being aliens, they wouldn't have known the difference if the Doctor and Sarah decided to shake hands instead.

Film

 * Colossus the Forbin Project. Dr. Forbin convinces Colossus that he is having an affair with one of his assistants as a means of gaining privacy for planning how to deactivate the computer.
 * The eponymous perfume in Perfume smelled so good, it forced a whole village square to erupt in a free-for-all orgy.

Literature

 * In the Isaac Asimov short story "What is This Thing Called Love?" a pair of mono-gendered aliens abduct a man and a woman in order to study human sexuality, since they themselves (And all other species that they have encountered) reproduce asexually. One of the aliens is a scientist who has started to figure out the "One species, two genders" concept, but the other is an officer who cannot wrap its mind around such a thing, and is disturbed by the very notion. While they try to get the two humans (strangers to each other) to mate, they are disturbed and offended. Fortunately, the adventure ends before either of them is forced to do what they will regret, since the scientist still did not have a firm grasp of sexual reproduction, having gotten much of his information about human sexuality from racy but non-explicit fiction. The captain cut the entire experiment short after their first kiss. Once released, of course, it is only natural that they spend a few minutes talking about the affair, and it only makes sense that they head inside for a drink, and since they are already inside.... Unfortunately for the alien scientist, their ship leaves the planet just as it notices this, and the captain never looks at the screen to see what it is so excited about.
 * In EE Doc Smith's Lensman books, the super-advanced Arisians are slowly breeding the ultimate humans by subtly encouraging the best and brightest to marry and have children.
 * As a reversal of the trope, the Arisians also make sure the two star lines do NOT mate before the proper time by making members of the opposite gender of each line dislike each other the closer they get.
 * Continuing the reversal, because humans are chosen to be the Children of the Lens, three other species who also have star lines are never allowed to mate and achieve their race's true potential.
 * Kurt Vonnegut's novel Slaughterhouse Five involves the scrawny main character and a porn star being abducted by aliens. They bang.
 * The aliens didn't force them to mate, although that was what they wanted. They did, however, put them together for the rest of their lives in the same house / cage as the only two humans on their planet.
 * With no clothes, either.
 * In the Worldwar (Literature) Alternate History novel series by Harry Turtledove, scientists of The Race (aka the Lizards) are so shocked to discover that humans don't have a mating season, they take several of their human prisoners aboard ship and force them to 'go screw' with random members of the opposite sex. They are even more shocked when some of these humans 'form permanent pair bonds' (i.e., fall in love), an idea that they meet with a mix of amusement and disgust.
 * The joke proves to be on them, however: when the colonization fleet arrives (the conquest fleet was all-male), they find to their chagrin that the powerful Earth narcotic 'ginger' has the side effect of causing females to go into season immediately. They end up sheepishly asking their human advisers for advice on how to deal with the inevitable changes this brings to their society (at least among the Earth/Tosev 3 colonists).
 * Back in the original series, one of these couples, Liu Han and Bobby Fior, are brought back to Earth later (to Liu's native China, specifically) when Han becomes pregnant. The experiment isn't quite over, however: after she gives birth they take her daughter, Liu Min, back up to the same research ship to see if they can raise a human as a citizen of the Empire. Han (who is now alone after Bobby's heroic but rather pointless death) joins a Maoist resistance cell in a bid to regain her. She eventually succeeds, despite the rather petty attempts of the Lizards to discredit her (by showing footage of the 'experiments' in public!), but she (and in the later books, Min) remains with the PLA, eventually become an important member of the People's Revolutionary Committee.
 * A running plot element in the Dragonriders of Pern series: When dragons mate, their riders will be compelled to mate with each other... even if they're both guys. Even those riders whose dragons weren't successful in catching the female will be overwhelmed with lust (for example, Jaxom going caveman on his holder girl paramour in The White Dragon). The matings of fire lizards (tiny creatures related to the larger dragons) are shown to have a similar but much milder effect. (The lust seems to be compelling only if there was pre-existing sexual attraction between the parties).
 * Not only that, but a mating dragon is known to spread the need around to anyone they happen to fly over. Though only the riders of the dragons involved are forced to comply, it's implied that the Weyrfolk have no problem with this phenomenon. It's a major reason for the Weyr's more open attitude towards sex in general, as green dragons are the most common type and frequently are known to be in rut.
 * Also, the extreme cold of Between, an inter-dimensional space dragons can cross, terminates any pregnancies that might result.
 * It terminates pregnancies only in first stages. A woman explicitly states that it happened to her because she was not aware yet of her pregnancy. Those who know they're pregnant avoid going between at all costs. It's also implied that it's used as form of abortion (Officially frowned upon, but most Weyrleaders and Lord Holders look the other way).
 * Kylara says in Dragonquest that it takes an "extra moment between" to cause an abortion, and I believe it's implied elsewhere that it's the repeated trips that harm Lessa's ability to have children. Basically, a few regular trips between does not necessarily terminate every pregnancy.
 * There was a short story by... someone, somewhere, called something... in which an alien charged with overseeing the Earth did this to everyone on the planet at once via Mind Control to stop them from starting a nuclear war. It worked until
 * A very dark example is Robert Silverberg's Passengers. The Earth has been invaded by disembodied intelligences with a taste for controlling individual humans. This trope is one of the nicer things they do to their victims.
 * Older Than Steam: In Cyrano de Bergerac's Voyage dans la lune, the Selenites capture the hero and treat him like a pet. The Moon Queen already has an human, and the Moon King is convinced that the hero is a female, and that they must mate. As they said, "the prince's will was thoroughly carried out."
 * In Kushiels Scion, mild mannered baron what's-his-name is possessed by his great-grandfather, transforming him into the legendary CAPTAIN SCOURGE, undefeated strategist, unrelenting swordsman, raider and murderer, in his epic struggle to utterly pulverize the enemy monster! Guess what he does to the baron's cousin.
 * In one for the Dresden Files short stories, a romance/sexual version of this happened due to a spell cast by a Red Court vampire as a weapon against the White Court vampires, who are Allergic to Love. Results varied from cute  to squicky  . The Red Court vampire tries to convince Harry that she's artificially creating love that's as good as the natural thing, but he doesn't buy it.
 * In another side story; magically spiked alcohol from one of Dionysus's Maenads. Dionysus being the god of (effectively) wild, raging parties (among a whole host of other things) it caused people to go into something between a rampage and an orgy. They had no memories of it, and the magical spike was very cleverly designed such that anyone who examined it directly would be affected as if they'd drank it.
 * This seems to be a theme of the Dresdenverse short stories, since it gives Butcher a convenient excuse to put Dresden and Murphy in various positions ranging from hilariously awkward to hilariously fanservice-y.
 * From the very first book: don't let Bob talk you into making a romance potion. And if you do, certainly don't forget to label it distinctly, such that, say, if you're fighting a demon that suddenly invaded your home and send your girlfriend to fetch a potion of escape, she should be able to tell the two apart. Because wouldn't that have been an awkward series of mistakes to make?
 * Mind Magic like this is very, VERY illegal in the Dresdenverse. Laws of Magic illegal. Death-by-decapitation on suspicion illegal. Guess what one of Harry's apprentice's specialties is?

Live Action TV

 * Buffy the Vampire Slayer had a house use Buffy-Riley sex as a battery for its haunted hijinks. After they are "rescued" and the haunting defeated, someone comments on how terrible the ordeal must have been for them. Buffy and Riley meekly agree while giving each other meaningful glances.
 * On Angel, this almost happened between Angel and Cordelia when they were both possessed by the ghosts of two lovers who were stuck in a Groundhog Day Loop. Notably, they actually induced the possession at one point so they could figure out what exactly was going on, but felt rather awkward when it went farther than they expected. Happened to Angel again later on, but with a different twist. Lorne's empathic powers were malfunctioning, which caused everything he said to be taken as a psychic command, so the alien making Angel and Eve do it didn't even know what he was doing at the time.
 * Star Trek the Original Series: When Kirk and Uhura performed one of television's first interracial kisses (though not the very first, as is commonly claimed - that was Sammy Davis, Jr. and Nancy Sinatra on Movin' With Nancy), it was because Aliens Made Them Do It. Literally. People still complained, even if in the end, the director cut away before actually showing their lips meet.
 * Nichelle Nichols says that the network made them shoot the scene with and without the kiss, and Shatner deliberately screwed up all the "without" takes to force them to show the kiss anyway.
 * In an episode of Star Trek Deep Space Nine, Weyoun orders that Worf and Ezri Dax be put in the same cell- he doesn't plan to force anything but reckons it would be fascinating to watch if anything did happen. Apparently they don't have Internet access in the Dominion, so he has to get his jollies however he can. He may also have just been making a joke.
 * Unfortunately for Weyoun, Worf didn't find him very funny.
 * Heck, this was the entire focus of the original pilot, "The Cage": the Master of Illusion Talosians telepathically put Pike and Vina into a variety of settings, hoping they'll tumble into each other's arms and begin the process of repopulating the planet.
 * Star Trek Voyager does it twice with Tom Paris and B'Elanna Torres:
 * In "Blood Fever", Torres' mating instinct is triggered by an accidental telepathic link with a Vulcan undergoing pon farr. It doesn't get consummated, but Paris hints at being interested afterward.
 * In "Scientific Method", after a lengthy Belligerent Sexual Tension courting, Torres suddenly declares that she loves Paris. Pretty soon, they're having passionate sex in not-so-private places (while on duty) at the drop of a hyperspanner, so much so that Captain Janeway has to reprimand them. It later turns out that invisible aliens have been on Voyager for some time running experiments on the crew. Afterwards, the two wonder if their entire relationship is due to aliens tweaking their hormones into overdrive. "Thank God we found out in time," they say (while kissing passionately).
 * Nagilum, the Sufficiently Advanced Alien antagonist of the TNG episode "Where Silence Has Lease" wants to observe the propagation of the species for curiosity's sake. Dr. Pulaski refuses to comply.
 * Blakes Seven did this twice: Tarrant and Dayna narrowly avoid being forced to have one off to satisfy the scientific curiosity of the Ultra in "Ultraworld", and Tarrant and Servalan come very close to reproducing to satisfy some intelligent sand that likes killing people (and Foe Yay, apparently), and therefore needs more people around to kill, in "Sand".
 * Almost but not quite three times, if you count the episode "Moloch" in which the "computer" decision on Servalan's punishment is to "give her to your men"; she winds up being "given" to Vila.
 * The evil government conspiracy forces Nikita and Michael of La Femme Nikita undercover as a married couple, under the watchful eye of a voyeuristic terrorist. Naturally, they simply must keep up their cover. Supposedly, the episode was specifically written to subvert fan demand for Nikita and Michael to get together, actually this episode entitled "Love" episode 6, was originally aired less than a month after the series premiered.
 * Red Dwarf also features this, A Psiren (not technically an alien as it's from Earth, one of the staples of the series) uses an illusion to make out with Lister, although it turns into a huge dung-beetle before they can copulate and attempts to suck out Lister's brain.
 * True Blood had Maryann, who enchanted the whole town in to a hedonistic orgy.
 * Torchwood briefly features Owen using salvaged alien tech as this.
 * On The 4400, Lily and Richard slowly discover that somehow, they conceived a child together during the time they were abducted. They had never met before their abductions (Lily had not even been born when Richard was taken) and had no memory of what went on during that time. It is never fully explained whether they had a romance they now could not remember, or had been part of an alien breeding experiment.
 * It is shown, however, that Richard and Lily's grandmother were a couple before Richard's abduction, suggesting perhaps that their abductors thought Lily was close enough to a woman Richard had previously been attracted to.
 * Steven Spielberg's Taken miniseries had a literal case, where the two parties were taken aboard an alien spaceship to breed with each other.

Video Games

 * Subverted in Persona 3: one of the boss battles in takes place inside a Love Hotel. After defeating the first Shadow, the party is Brainwashed by a second, hidden Shadow. This is subverted, however, in that they manage to break free from the mind control before things go too far. (The game does not give you the option of actually giving in.)
 * Way back in Final Fantasy 7, the mad doctor Hojo puts Red XIII and Aeris in the same cell, since they are both presumedly the last of their species, and he hopes to mate them. He doesn't take into consideration the fact that Red XIII is a quadrupedal lion-like creature while Aeris is, for all intents and purposes, a human. Needless to say, no mating of any kind occurred.
 * Many, many 'Mons games featuring Hot Skitty-On-Wailord Action put the Player in the position of allowing his 'mons to breed. Odds are good that the cactus & the sumo wrestler would probably not have gotten together on their own....
 * A Manipulative Bastard mage (arguably the Big Bad) in Fire Emblem Jugdral brainwashes a noble and his half-sister into breeding a new vessel for a dark god.
 * In the X-rated visual novel Euphoria, the characters awaken in a mysterious windowless room and are forced into a sadistic "game" where they have to comply with the (primarily sexual) orders of a disembodied voice under pain of death.

Webcomics

 * In Platinum Grit, aliens arrive to try and help a mortally embarrassed Jeremy sleep with a rather bemused Nils. This keeps everyone busy for two whole issues, and naturally.
 * This Saturday Morning Breakfast Cereal.
 * In a small General Protection Fault story arc, aliens don't techncically force Fooker and Trudy, but wouldn't let them go until they did. However, Trudy managed to talk her way out of it.

Web Original

 * An interesting inversion played for laughs in Dragonball Z Abridged: Nappa forces the king of the Bug People to have sex with his wife. Vegeta finds this very disturbing.

Western Animation

 * Aside from the trope quote, an episode in the new season of Futurama has Zapp attempt to enact an Adam and Eve Plot on Leela, the only way the man would ever score with her again (he used up the pity card the first time). Though Leela figures out what he's up to, a Death Star-like censorship satellite demands that they copulate, since it sees said plot as one of the few good things about humanity. Leela is a good sport and takes one for the team. Zapp however didn't enjoy having an "audience". Likewise, Fry did not enjoy being the audience.
 * The Simpsons had a Treehouse of Horror episode where Maggie turned out to be the result of Kang impregnating Marge. The whole thing was Played for Laughs (the aliens provide Marge with several backdrops, like the backseat of a car and the alley behind a porno theater), and there's a Does This Remind You of Anything? moment where the insemination is done via ray gun and Kang gets offended when Marge says "That was quick."