->"She has a newness," he said. "Everything is for the first time... If I had learned she had been born this very morning, I would only be surprised that she was so old."
-->-- '''Prince Lir''', ''Literature/TheLastUnicorn''[[note]]This is said the first time he sees the unicorn, who was indeed changed into a human woman only the previous night.[[/note]]

Subverting the old joke, this character ''really was'' born yesterday, or this week at least, either [[RapidAging artificially aged]] or just plain [[BornAsAnAdult made the age they are now]]. They tend not to understand slang, or much of anything else, and will misunderstand social rules with [[HilarityEnsues usually comic results]]. May also be the result of a person being born normally but kept in some kind of stasis and never being conscious during their development since they still awake as a 'new' person.

Contrast ReallySevenHundredYearsOld, compare EmergentHuman, PinocchioSyndrome. They're often prone to BluntMetaphorsTrauma as well. Can be coupled with ArtificialHuman if they were recently created. The extreme end of YoungerThanTheyLook. Pairs well with BornAsAnAdult.

'''Note:''' Please be careful when adding robot examples as, broadly, they almost all count. As a general rule examples should be kept to those that act in a way that is very strongly reminiscent of the Trope description. RealLife examples may be added but should be related to medical conditions.



[[folder:{{Anime}} and {{Manga}}]]
* Combat Cyborgs Otto, Deed, and Sette from ''Anime/MagicalGirlLyricalNanohaStrikers'', who, despite looking like teenagers, have barely a month of real memories (since they were artificially aged and imprinted mainly with combat skills).
* Chii in ''Manga/{{Chobits}}''. Not in a physical sense, her body is a robot that has existed for a while. But she's dead at the beginning of the series, and in the first episode she gets reincarnated into her own body. Her new self is very much born yesterday, having to learn everything.
%%* In ''Manga/{{Trigun}}'' at least two of the characters are like this.
* Yuki of ''LightNovel/HaruhiSuzumiya'' appears to be a high-schooler but is really a three-year-old [[HumanAliens alien interface thingy]]. [[spoiler:Asakura]] is similar. They fit the trope even more closely later in the series, when Kyon and Mikuru meet them three years in the past and they ''still'' appear to be high-school age. And since the event that was the reason Yuki [[spoiler:and Asakura]] were created (something about data created by Haruhi and the potential for evolution) happened on Tanabata three years ago, and Kyon and Mikuru went back to that same day, it's probable that they were only a few hours old or even less at that point.
* ''Anime/NeonGenesisEvangelion'':
** In the manga version, [[ArtificialHuman Kaworu]] is only nine days old when first introduced. As such it's really no surprise that he has NoSocialSkills and does things like accost Shinji in the shower while they're both naked.
** Rei Ayanami also counts in certain versions. The "first" Rei who looks like a child in a flashback is hinted to be much younger than she appears, and thanks to the BodyBackupDrive that is the "Reiquarium" she's effectively reborn whenever her soul is put into a new body. This effectively resets her personality [[spoiler:but only to a point, as Gendo discovers to his dismay in ''End of Evangelion''.]]
* The title character of ''Manga/MyDearMarie'' literally tells the rest of the cast she was in fact born yesterday, much to the consternation of her creator who is barely trying to cover up the fact she's a robot copy of the girl he has a crush on at school (Mari). That she does in fact act like this doesn't help either. Luckily, the real Mari just assumes she means it was her birthday.
* ''Manga/MahouSenseiNegima'': It's noted at several points that despite being a middle-schooler, [[RobotGirl Chachamaru]] is technically only two years old.
* ''Manga/UQHolder'': [[spoiler:Touta Konoe]] doesn't have any memories from before about four years ago, and believes he has amnesia. Turns out, nope, the reason he doesn't have memories going back further is that he didn't ''exist'' until four years ago.
* In ''Anime/KemonoFriends'', the titular Friends are all LittleBitBeastly girls born from a live animal or biological samples of them coming into contact with [[{{Phlebotinum}} Sandstar]], and most of them are probably much younger than their appearances would suggest. The best example is definitely [[spoiler:Kaban/Bag, the TokenHuman]] who is at most a few days old by the end of the series since she was born during the last Sandstar eruption after a bit of it came into contact with [[spoiler:a human hair inside a lost hat]].

[[folder:Comic Books]]
* ''Comicbook/YoungJustice'': ComicBook/{{Superboy}}. His exact age depends on the continuity, but he's generally freshly cloned.
* In ''ComicBook/{{Transmetropolitan}}'', The Smiler's original pick for a vice presidential candidate was a two-year old first-term representative who had been cloned. He had a completely clean record, and no baggage from past scandals -- that is, except the scandal of his actual identity.
* Madelyne Pryor, Scott Summer's first wife in ''ComicBook/XMen'' was eventually {{retcon}}ned into a clone of Jean, but despite this she's pretty well socially adjusted until she goes nuts after Scott abandons her.
* Tesla, the title character in ''ComicBook/TheClockworkGirl,'' is only a day or so old when Huxley first takes her out to see the natural world. She's delighted with all the things she's seeing for the very first time. He responds that he thinks he's never really seen them before now, either.
* [[spoiler: Tailgate]], in ''ComicBook/TheTransformersMoreThanMeetsTheEye'' ends up being this: when we meet him, he's been in a form of stasis for six million years, long enough to be a peer of [[ReallySevenHundredYearsOld Cyclonus,]] which should make him one of the oldest members of the cast. [[spoiler: However, at one point, he reveals that he was created at Rivets Field. Cyclonus is surprised at this, pointing out that Rivets Field didn't fire up until shortly before the incident that placed him in stasis. Tailgate only confirms it: his body may have lasted eons, but his mind at the start of the series is only two weeks old.]]
* Victor from ''ComicBook/{{Runaways}}'' is a two-year-old cyborg who was built as a teenager and given fake memories to make him ''think'' he's a normal human teenager.

[[folder:Fan Fiction]]
* The ''Fanfic/AnAstralDropInHeatherfield'' starts with Hope's literal moment of creation and ends only two months later - although she packs a lot into her first few weeks alive.

[[folder:Films -- Animation]]
* ''ComicBook/TheSnowman''
* ''WesternAnimation/FrostyTheSnowman''
* ''Disney/{{Pinocchio}}'', a boy is carved from wood and brought to life.

[[folder:Films -- Live-Action]]
* ''Film/AvengersAgeOfUltron'':
** Ultron himself serves as an example; though unlike [[spoiler:The Vision who's described as naïve]], Ultron's lack of life experience, combined with a quick internet download, [[spoiler:drives him insane and convinces him that [[OmnicidalManiac Humanity needs to be culled.]]]]
** Invoked when Ultron [[spoiler:accuses the Vision of naïveté.]]
--->[[spoiler:'''The Vision:''']] Well, I was born yesterday.
* Leeloo in ''Film/TheFifthElement''.
* The Phoenix in Music/KanyeWest's ''Runaway''
* Lisa in ''Film/WeirdScience''.
* To a limited extent, Simone in ''Film/S1M0NE''

* Literature/TheBible: Adam, then Eve.
* F. Scott Fitzgerald's ''The Curious Case of Benjamin Button", and the [[Film/TheCuriousCaseOfBenjaminButton film of the same title]]
* ''Literature/TheAdventuresOfPinocchio'', the original source.
* ''Literature/TheLastUnicorn'': The page's quote at the top is about Lady Amalthea, who is immediately noticeable as having a "newness" to her--each movement she makes indicates that she's doing many things for the first time. This happens to be because [[spoiler:up until that point, she was a unicorn]].
* Elva from Christopher Paolini's ''Literature/InheritanceCycle'' aged physically to around five years old within a few days of her birth [[spoiler:because Eragon, in his attempt to bless her newborn self, bungled a syllable and accidentally [[CursedWithAwesome cursed her with the ability to "be a shield from harm" (instead of "being shielded from harm")]] ]]. What's even creepier is that while she aged physically to around five in that time, she mentally developed the intelligence, reasoning capacity, and ''cynicism'' of a woman with several decades under her belt.
* ''Literature/ASeriesOfUnfortunateEvents'' mentioned the idiom in one of the books, telling how you (the reader) were probably not born yesterday. The author adds, [[LemonyNarrator "Unless, of course, you were born yesterday, and in that case, welcome to the world, little baby, and congratulations on having learned how to read so early in life."]]
* Thallo, from ''Paul of Dune'' is only nine, but appears seventeen or eighteen years old, his physical growth having been accelerated by his creators.
* [[spoiler:Gaia]], from the ''Literature/{{Gone}}'' series, was born four months after conception as a fully formed infant, and looked about sixteen years old after birth.
* The Scarecrow from Literature/TheWonderfulWizardOfOz was born two days before he met Dorothy for the first time.
* Ed'Bocaj from ''Literature/AlmostNight'' appeared as a child when she was but hours old, and reached full adulthood in days, and was born with the mind of an adult, though she acted childish for fun.

* Various characters in ''Series/DoctorWho''.
* Luke and Sky Smith from the ''Series/DoctorWho'' spinoff ''Series/TheSarahJaneAdventures''.
* Liam Kincaid, the protagonist of ''Series/EarthFinalConflict'' for seasons 2-3. Born with three parents (one of them an alien) he grows from infant to adult over less than one full episode.
* The classic ''Series/TheOuterLimits1963'' episode "Demon with a Glass Hand" [[PlayingWithATrope plays with]] this trope. Trent, the protagonist, begins the story by musing, "I was born ten days ago. A full grown man, born ten days ago." Actually, [[spoiler:he's a robot from 1000 years in the future built to protect humanity from genocidal invaders.]]
* Dawn Summers in the fifth season of ''Series/BuffyTheVampireSlayer.''
* ''Series/KyleXY'': The title character spent the first 17 years of his life gestating in an incubation chamber.
* Adria, the humanoid CrystalDragonJesus of the Ori in ''Series/StargateSG1'', is carried for 9 months and born like any other baby, but she ages to young adulthood in about 24 hours.
* ''Series/{{Supernatural}}'': Dean's daughter Emma, [[OneGenderRace an Amazon]], is conceived, born, and becomes a young adult within a couple of days.

* A common occurrence in ''TabletopGame/{{In Nomine}}'', where the angel or demon who was first sent to Earth this morning will nonetheless usually be wearing a body that looks like an adult human.
** Although they aren't usually sent to Earth immediately after their creation, still there's a major learning curve for those new to Earth no matter how old they actually are, and it has much the same effect.

* In ''Theatre/TheWiz'', the Scarecrow's IAmSong is called "I Was Born on the Day Before Yesterday".
* Rocky in "The Rocky Horror Show" (and its [[Film/TheRockyHorrorPictureShow film adaptation]]) is actually born onstage during the song "I Can Make You a Man". He's a real hunk of a man-baby, and (naturally) has the mind of a toddler, which makes it kind of concerning that his first sexual experience happens when he's less than a day old.

* Baton, the heroine of ''VideoGame/TadpoleTreble'' is literally born at the start of the game, thus making the first level a JustifiedTutorial, as her parents teach her the way the world works. Her curiosity also gets her caught by Coda the pelican when she ignores her mother's warning, setting the stage for the rest of the game. Sonata, another tadpole met in Midnight Bayou, is described as also being born yesterday in the Bestiary, which makes his [[PuppyLove sophisticated serenade to Baton]] that much funnier.
* The Sylvari from ''VideoGame/GuildWars: Eye of the North'' and ''VideoGame/GuildWars2'' are this, as they are a new race just getting their foothold. You actually get to see the 'birth' of the first Sylvari in a cutscene in Eye of the North.
* Grunt from ''VideoGame/MassEffect2'' is a [[DesignerBabies Designer Baby]] SuperSoldier and the only one of thousands that his Krogan creator Okeer thought was worthy, and he's basically born in your cargo bay when you release him from his tank. He does come with some NeuralImplanting, but you're the first person he actually talks to outside of Okeer talking to him while he was in his tank (when he was unable to respond). He was also deliberately designed to have his armored headplates not be fully fused together, unlike the adult Krogan, which is reminiscent of how the pieces of a human newborn's skull aren't fully fused until some time after birth.
* KOS-MOS from ''VideoGame/{{Xenosaga}}'' is activated for the first time during the events of the first game. [[spoiler: Although she does share data with a buggy prototype that was activated once before.]]
* Rika from ''VideoGame/PhantasyStarIV'' is one year old, but looks just a little younger than Kyra, who is 18
* [[spoiler: Klaymen himself]] in ''VideoGame/TheNeverhood.'' The world is a kind of Eden (both metaphorically and, er, [[RuleOfSymbolism metaphorically]]), so it's not surprising there would be some literally new people in it.
* Mileena in ''Franchise/MortalKombat'', didn't qualify for this Trope for most of the franchise, which claimed she grew up with her “sister” Kitana, and was thus several centuries old. However, in ''Mortal Kombat 9'', the RetCon changes this so that Kitana meets her in the Flesh Pits right after she was “born”, meaning Mileena is more-or-less an infant (although "born" fully grown) as far as her true age is concerned.
* Roxas in [[VideoGame/KingdomHearts358DaysOver2 Kingdom Hearts 358/2 Days]] in the game's first hours. He barely knows any words, doesn't know what friendship means and he is clueless about just everything. Later on, he develops more and grows a spine, gradually becoming the way he was in Kingdom Hearts II. Justified because [[spoiler: he is Sora's Nobody and born without any of his original self's memories]].
* ''[[VideoGame/AdvanceWars Advance Wars: Days Of Ruin]]'' gives us [[spoiler:Isabelle, a very recently created clone who is believed to be suffering from amnesia when in reality she's never had any memories to begin with.]]
* All of the [[ArtificialHuman Murakumo Units]] ''VideoGame/BlazBlue'', to varying degrees.
** Lambda-11 is of unknown age, but dormant until Kokonoe activated her during ''Continuum Shift''. She awkwardly bonds with an insect in her story mode, but otherwise acts almost completely mechanical and obedient.
** Mu-12 ([[spoiler:Noel Vermillion]]) has been active only 5 years at the start of ''Calamity Trigger''. It's unknown how much of this effect and her lack of memories contribute to her painfully shy personality, but she is still the most social of the Murakumo units.
** Nu-13 is first activated during the events of ''Calamity Trigger'', and can do little but destroy and {{yandere}} over Ragna.
* Along the same lines as above, the ''VideoGame/GuiltyGear'' games have the Command Gear, Dizzy, who is technically only 3 years old, even though physically she looks like a young woman in her late teens or early twenties, due to the rapid development granted by her Gear cells. She's rather kind-hearted and gentle for a Gear, although this inevitably also comes with some social naivete.
* In ''{{VideoGame/Overwatch}}'', Orisa stands out as the exception to the robot rule mentioned about because her stated age is 1 month old, having been created by the (pre)teen genius Efi Oladele from the remains of an OR-15 robot that was destroyed in an attack by Doomfist. The developers specifically bring this up as something that makes her stand out from other heroes in the 'verse, some of whom have histories going back decades, and cited by Efi and herself as why she's still getting the hang of this whole "hero" business. For comparison the other Omnic who's a playable character, Zenyatta, is 20 years old and is portrayed as a wise mentor figure, even to characters who are older than he is.

* In ''Webcomic/FarOut'', this is suggested to the main character as a possibility, instead of amnesia. Given he's a robot, it's a real one.
* In ''Webcomic/TheInexplicableAdventuresOfBob'' this is the reason the three peanut butter monsters--Molly, Golly, and Jolly--act so immature. They're only a matter of months old. The only reason they don't act like ''infants'' is that they're hyper-intelligent and learn quickly.

* Belphoebe in the ''Literature/WhateleyUniverse'' is a cloned drow created by one student (Belphegor) using the cloning chamber he'd stolen from another (Jobe Wilkins) and accidentally imprinted with a copy of his own memories. Hence while chronologically she's 0, she looks 16 and is considered that age by the administration, staff and students.
* Hanazuki, the title character of ''WebAnimation/HanazukiFullOfTreasures'', was born in the first episode, and we're reminded of it in episode two when she tells Sleepy Unicorn she ''was'' born yesterday.

* Peep in ''WesternAnimation/PeepAndTheBigWideWorld'' is a baby male chicken about as intelligent as a human first grader. In one episode he recalls his entire life, which actually did start yesterday.
* ''WesternAnimation/YoungJustice'': Superboy. Not quite "yesterday" but he's [[ArcNumber 16 weeks old]] in the first episode.
* ''WesternAnimation/Ben10UltimateAlien'': Eunice is a 16-year old girl [[NakedOnArrival who is found on a spaceship]], and later in the episode is discovered to be a Unitrix splicing Gwen's DNA.
* The Canadian animated short ''To Be'' involves a teleporter that works by duplicating the "passenger" and killing the original. The film is about the inventor getting called out on the immorality of this. After the protagonist is responsible for [[spoiler: one iteration of the inventor getting killed, she atones for the crime by teleporting herself, reasoning that the guilty her has been executed, and the "new her" is innocent.]]
* In ''WesternAnimation/GetEd'', Ed was "electrogenetically engineered" and acts like he hasn't been around more than a few months. While he's already good friends with his teammates at the start of the show and knows about the basics of life like eating and bathing, he's still utterly amazed when he learns that "those signs with numbers on them" are ''the speed limit'' (you'd think ''a courier'' would know that) and generally tends to be naive.
* The copies of Pinkie Pie from the mirror pool in ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' all have her [[GenkiGirl same]] [[CloudCuckooLander personality]], but none of the knowledge, memories, or life lessons the original has learned throughout the course of her life. The result is a large number of obnoxiously destructive versions of Pinkie Pie (In other words, it's not pretty).
* ''WesternAnimation/StevenUniverse'':
** Concept art for "Hit The Diamond" implies that one member of the [[AdorableEvilMinions The Ruby Squad]] sent to Earth, the one with the gem in her leg, was literally created one day before their mission, which explains her NaiveNewcomer personality and general lack of self-confidence.
** In "Know Your Fusion", [[spoiler:Smoky Quartz]] points out that they don't know that much about themself yet as, between their debut episode and this one, they've literally existed for about ten minutes total.
* In the ''WesternAnimation/StarFairies'' TV special, True Love, Whisper, Jazz, Spice, and Nightsong were created in an instant, and are instructed as to who Sparkle is and who they are.
* Cubert from ''WesternAnimation/Futurama'' was cloned from one of the Professor's more shapely back growths, and was born as a young boy of around ten.

* In very rare cases, a person's brain can lose track of its entire memory making it seem like it has been 'wiped', such as in [[http://www.bbc.co.uk/news/health-13627118 this example]]. Victims generally retain a few links and don't lose everything, though it can happen ([[ParanoiaFuel there are also very rare conditions where every memory can vanish, just like that, and with no warning at all]]).