Hiccup: Eh, should I... Should I know you?
Valka: No. You were only a babe... But a mother never forgets.
A parent-child bond is strong enough that even in situations where the child is in disguise, is being impersonated by someone else, or is in the midst of a crowd of look-alikes, the parent can still identify him or her.
Commonly associated with mothers due to the maternal bond that's usually created through pregnancy, childbirth, and the early years of child-rearing. However, this phenomenon isn't limited only to mothers, as fathers and other relatives can qualify for this as well.
Compare Something Only They Would Say, which is where a character who's in disguise or whose identity is uncertain makes himself known by saying or doing something that only they would normally do. May also overlap with Spot the Imposter in some cases, but it is NOT the same trope. Contrast Doesn't Know Their Own Child.
Also not to be confused with That Thing Is Not My Child!, where a person denies parental responsibility to a child because said child was born via cloning or other unnatural means.
An inversion of this trope would be the child being able to identify his/her parents despite the specified conditions.
NOTE: To qualify for this trope, the persons MUST be related, whether by blood, adoption, or some other family-related clause. True Companions don't count, as while they may have the semblance of family ties, in the strictest sense of the word they are not family and generally haven't raised the child/children from birth or infancy.
- Tenchi Muyo!:
- In the OVA, while Yosho's false persona of Katsuhito Masaki had been known fact for a while, his mother sees right though his disguise of being old, which was part of that persona, and asks him to take it off. No-one else knew about that.
- In the movie Tenchi Muyo in Love, Achika recognizes Tenchi as her son, despite the facts that she is in high school, unmarried, not even dating, and Tenchi won't be born for another nine years.
- In Dragonball Z an inversion of this occurs during the Namek saga. Captain Ginyu has switched bodies with Goku, planning to use this to his advantage when he meets Krillin and Goku's son, Gohan. Before Ginyu can even open his mouth, Gohan is quick to tell Krillin "That's not Dad!"
- In Parasyte, mothers seem to have this. The parasite who took over Ryoko Tamiya had to kill her host's mother, who could somehow tell that she was an "imposter" and tried to call the police; the parasite is initially confused how she managed to figure this out. Likewise Shinichi's own mother realizes that something is wrong with him, despite the fact that he's (at least mostly) retained his normal personality.
- Kasane: When Nina's mother first met Kasane impersonating Nina she immediately noticed that there's something different about "Nina" and she ultimately realizes that Kasane is not Nina. Nina's father, on the other hand, averts this trope and Kasane convinces him that the mother suffers from the Capgras delusion.
- Averted in Zekkyou Gakkyuu. Rika's mother fully believes that the transformed Mary is her own daughter, and pays no mind to her real daughter trapped in a doll's body on the shelf.
- After The Death of Superman, four individuals turn up, each of them claiming to be Superman. Pa and Ma Kent know right away the Metropolis Kid can't possibly be their son because Clark would never behave like a delinquent. In fact, Pa Kent said that none of them is their son, any more than he is the king of England.
- In Superman Family story "Strangers at the Heart's Core!", Lesla-Lar takes over Supergirl's body in an attempt to steal her enemy's life, but she fails to fool Kara's parents. Zor-El points out that their daughter would never call them by their first names, and Alura states she just knows her own daughter.
Alura: There was something else about you that wasn't right! A mother knows her own flesh and blood...
- In one Spider-Man story, the Chameleon has seemingly tricked Aunt May into thinking that he's Peter, only for her to correct him of that notion—she is, after all, Peter's mother in all but name, and he could never fool her. Oh, and by the way, those cookies that she offered him were poisoned.
- The Buffy the Vampire Slayer fic Time and Time Again features Katie Summers, the Dhampyr daughter of Buffy and Angel who travels back in time to prevent Buffy's death at Glory's hands. While Angel has to be told as such, Buffy, despite still being in a relationship with Riley at the time and having been told by Angel that vampires can't have children, is able to deduce on her own that Katie is her daughter.
- Played with in the Jackie Chan Adventures fanfic The Ultimate Evil: when the canonical Living Statue of Lo Pei meets Valerie Payne, he believes her to be his daughter Lo Mei because she has the same crystal blue eyes. He also thinks the physical differences to be a result of magical concealment and lampshades this trope by saying that any father can know his beloved child anywhere. While the living terracotta is mistaken, Valerie is Lo Pei's descendant by 36 generations.
- In the Miraculous Ladybug fanfic The True Villain, Marinette (the titular superhero) is shocked to discover her parents know about her heroics. Her mother admonishes her for this, saying "You insult me, Child. I can pinpoint your voice in a crowd of almost a hundred people. I'm pretty sure a little red mask is not enough to hide you from the gaze of your mother."
- In Time Fixers: Nicktoons of the Future, Cindy reveals that she was able to recognize Maxwell as the future version of her infant son when her husband isn't.
- Subverted in Boys Do Tankary. Nyra's mother gave her youngest child, Vincent, up for adoption, not even bothering to give him a name. Years later, when Nyra contacts Vincent, Nyra's mother assumes Vincent seduced Nyra, when Nyra's actual reason for calling Vincent was to reach out to him as his sister.
- Infinity Crisis: In Gamma Relations, Magneto feels there's something about the Maximoff twins but is unable to define what.
- In Batman: Angel of Death, when Azrael's mask is broken off, Catwoman instantly knows the woman underneath is her younger sister, Maggie, despite how they haven't seen each other in almost two decades.
- Inverted in the final chapter of The Second Try where a four year old Aki is able to recognize her parents despite both of them both of them being significantly younger than when she last saw them a day prior (from her perspective) and her not even knowing that she time traveled.
- Spirited Away:
- Inverted when the protagonist's parents have been transformed into pigs; to rescue them, she must pick them out of a line-up of several dozen other pigs. She correctly determines that none of the pigs are her parents.
- Subverted at another point in that Yubaba cannot recognize Boh transformed into a mouse. Of course, the fact that he was turned into a mouse is a more substantial handicap than normal.
- In How to Train Your Dragon 2, Hiccup's long-lost mother, Valka, is ultimately able to recognize him despite the fact that she hadn't seen him since he was just a baby (and Hiccup is 20-years-old when they finally reunited).
- Tangled: Implied to be the reason Rapunzel's mother recognizes her in the end despite her trademark long blonde hair chopped and brown by the end of the film.
- In Hey Arnold! The Jungle Movie: Arnold finally reunites with his parents, Miles and Stella, and they're instantly able to recognize him even though they hadn't seen Arnold since he was just a baby. Though, to be fair, the unmistakable Arnold still had the same hairstyle since birth and was wearing the hat they gave him.
- In Jett Jackson: The Movie, this is how Miz Coretta, Jett's great-grandmother, figured out that Jett had switched places with his TV role, Silverstone. When Silverstone asks her how she knew, she says that from the moment she first looked into the then-newborn Jett's eyes, she knew she would always be able to identify him. This information later becomes important in defeating the shape-shifting Big Bad in Silverstone's world when he makes himself look identical to both Jetts.
- In the remake of The Parent Trap, the father looks each twin in the eye and declares which one is Hallie. We never find out if he's right though since the twins keep playing up the charade and make him question his own judgment.
- Stardust: Una and Yvaine are captured by the witches. Tristan, trying to rescue Yvaine, mistakes Una for one of the captors and is about to attack her when she identifies herself, having recognized him even though the last time she saw him was when he was an infant.
- Changeling, a 2008 movie based on true events, is kick-started when a missing boy is returned to his mother—but she immediately realizes it's an imposter. She is committed to a mental institution when she refuses to acknowledge the boy as hers. It's a ploy by the kidnapping case's lead investigator to cover up the police department's incompetence and corruption.
- Horribly subverted in the Korean film Horror Stories, where a Wicked Stepmother fails to recognize her daughter was killed and turned into pickled meat that she was eating. The heroine, who knew the truth, is appalled.
And you call yourself a mom?
- The Moomins: Finn Family Moomintroll has a case of this, where everyone is playing hide and seek, and Moomin decides to hide under a hat which nobody knows to be an artifact which randomly shapeshifts whatever is inside. Naturally, nobody recognizes him afterward. In the end, he turns to his mother for help, she takes a look and says "Yes, that's Moomin". This also reverses the magic.
- Subverted in Tree Castle Island by Jean Craighead George: after Jack discovers on a camping trip that he has a long-lost twin named Jake, and the two return to civilization, Jack's mother (adoptive mother, never knew he had a twin until now) insists that she recognizes the boy she's raised. She goes and stands in front of Jake, not realizing that the two had switched where they were standing when she wasn't watching.
- Heckedy Peg, a children's picture-story book, provides a variation: an evil witch turns seven children into seven different types of food. Their mother tries to rescue them, but the witch says she will only change them back if she can guess which child is which food item. She guesses right.
- She's Not There:
- Gets discussed by Caroline, who always thought that she would instantly just recognize her missing daughter if she were to ever see her again. But when she actually meets Lili, the girl who thinks she might be the missing daughter, she cannot feel anything that might let her know.
- Played with, as the grandmother just smiles at Lili and flat-out says that Lili is the missing Samantha, claiming that she can see a young Caroline in her face. The rest of the family is unsure if they should believe her.
- Harry Potter
- Double Subverted by the twins Fred and George, who indignantly claim that their own mother can't tell them apart when she gets their names wrong... only to reveal that she got it right in the first place. And then there are their monogrammed Christmas sweaters, where they claim to be Gred and Forge.
- This trope is brought up in Harry's internal narration in Harry Potter and the Deathly Hallows, where he notes that Ron is avoiding looking into his father's eyes while under the Polyjuice Potion for fear of being recognized. However, considering Harry's earlier use of the potion had Luna Lovegood see straight through it because of his expression, it seems it's not just limited to parents.
- Discworld Averted for Moist von Lipwig, who is so nondescript (an invaluable skill for a conman) that his mother often ended up picking up the wrong kid from school.
- CSI episode "Split Decision" — identical quadruplets are involved in a killing conspiracy, even though one was a lot younger due to the in vitro fertilization aspect of the story. The mom of one of the four said she'd know him anywhere, but didn't know the other quadruplet who'd been ID'ed at the time.
- In Fringe, during Season Four, although Peter is both out of his original timeline (making him unknown to everyone in the current one) and in the other universe, his mother Elizabeth still recognizes him as her son grown up.
- Played with in Angel in which Illyria disguises herself as Fred in order to trick Fred's parents into believing that their daughter is still alive and well. They seem to fall for it... though as she's about to leave, Fred's mother wonders if there's something a bit "off" about her daughter, before shrugging it off.
- Subverted in the SVU episode "Bullseye." A mother suffering from Capgras Syndrome insists her daughter is an imposter, though she does recognize her daughter's voice when she can't see her.
- The Outer Limits (1995): Downplayed in "Time to Time". The 25-year-old Lorelle Palmer from 1989 travels back in time to April 14, 1969, and meets her parents Tom and Angie. Both of them find her very familiar and Angie automatically trusts her for reasons that she can't explain but neither makes the connection.
- Krabat is a Sorbian legend about a beggar boy who is called into the "black mill" by an old evil magician/miller where he learns, along with other boys, how to perform magic. In one version of the legend, Krabat reads without permission in the magician's book. The magician then transforms all of the boys into ravens. Only Krabat's mother is able to save him because she can pick him out of all the other birds.
- The German folk song "Hänschen Klein" is about a boy who walks the earth for seven years. He grows up and decides to come home, but nobody recognizes him anymore. His mother saves the day by looking into his eyes.
- Subverted in Oedipus the King, as Jocastas failure to recognize her son (who she believed to be dead after being abandoned as a baby) leads to the events of the plot.
- Inverted in Devil May Cry, where Dante could recognize Trish (who has his mother's face) even when she was disguised as Gloria.
- King's Quest III: To Heir Is Human: Upon being rescued, Rosella has very little skepticism that her rescuer is her long lost twin brother, though she can still ask for verification by having Alexander-Gwydion reveal his embarrassing birthmark.
- In King's Quest VI: Heir Today, Gone Tomorrow, if Cassima's parents are brought Back from the Dead, they can identify that the Cassima who is so eager to marry the Vizier is definitely not their daughter. It helps that she also indulges in a bit of Something They Would Never Say.
- In The Legend of Zelda: Majora's Mask, the Deku transformation that Link gets is the result of a Deku Scrub getting cursed by the Skull Kid into an inanimate form and the Scrub's form being subsequently used to curse Link. But the Deku Butler, the father of said Scrub, never mistakes Deku Link for his son despite remarking upon the resemblance. This is in contrast to Goron and Zora Link being mistaken for Darmani and Mikau, respectively, who did not have any relatives in the story.
- In Fate/Grand Order, King David immediately realizes Dr. Roman is really his son Solomon, but agrees to keep the secret.
- Implied in TRON 2.0. There are a few points where Benevolent A.I. Ma3a refers to the protagonist as "Jet" and not "Alan-2" (his login), and when corrupted by bugged code, fights it off long enough for Jet to run . As we find out through the Story Breadcrumbs, Ma3a is the Virtual Ghost of Jet's mother (who was killed in a Freak Lab Accident in this timeline) with her consciousness compiled into the AI.
- In the Family Guy DVD movie Stewie: The Untold Story, Future Lois is able to recognize her infant son when the rest of the family isn't.
- In the pilot of She-Ra: Princess of Power:, it's established that Princess Adora was kidnapped as an infant. When Prince Adam brings the now-adult Adora into the throne room, King Randor and Queen Marlena immediately recognize her. Man-At-Arms also recognized her.
- There are also several hints dropped in He-Man and the Masters of the Universe (1983), most notably in "The Rainbow Warrior", that Queen Marlena knows Prince Adam's secret identity, but doesn't say anything.
Prince Adam: I was wondering when Skeletor had us all chained up, why did you free me instead of one of the others?
Queen Marlena: Because you are my son, Adam. I didn't have time to free everyone. And I had a... feeling you would know what to do.
Prince Adam: Mother, ah...
Queen Marlena: Adam, a mother always knows her own son. And what he is capable of doing.
- On The Cleveland Show, when Roberta is made to disguise herself as a fat girl as part of a school project, no one at school recognizes her and Junior ends up falling in love with her. When she agrees to go on a pity date with him and he introduces her to the rest of the family, they all somehow recognize her instantly.
- A played with version occurs in Young Justice, where M'gann brings Sportsmaster and Cheshire into Artemis' mind to prove to them that Tigress is an enchanted disguise from a glamour charm and she isn't really dead. Cheshire, Artemis' sister, believes, but their emotionally abusive father doesn't. Instead, Artemis convinces him by using a fighting technique he taught her.
Cheshire: Come on, Crusher! Artemis is your daughter. Can't you feel her presence here?
Sportsmaster: This is just some Martian mind game. Right now, I don't even feel your presence.
- The Simpsons:
- Happens in a roundabout, comedic, yet oddly heartwarming fashion in "The Principal and the Pauper", where it's revealed Principal Skinner isn't the real Seymour Skinner. The real one "died" and he kept up the charade after coming back from the Vietnam War because he couldn't stand to upset the real Seymour's mother. Still, it's implied that she knew deep down he wasn't really her son; she has to tell him where "his" room is in the house after all.
- Played for Laughs in an episode where Bart and Lisa went missing while on a field trip. While searching the area where they were last seen, they find something and Marge gasps — it's the plastic tip from Bart's shoelace! When the others give her a look, she simply says "A mother always knows."
- Inverted in Star Wars: Clone Wars, where male Nelvaanians were being mutated into Super Soldiers. The women of the tribe are initially horrified when Anakin rescues them... until a young girl recognizes her father.
- In an episode of Star Wars Rebels, Ephraim and Mira Bridger hear their son's voice in a rebel transmission. Ezra has been separated from his parents for nearly nine years, during which time he's grown from a kid to a teenager and his voice has broken, but they recognize him anyway. What also sold it was that specific words in the speech were exactly what Ezra's parents taught him.
- Steven Universe: White Diamond is Pink Diamond's "mother", and instantly recognizes Steven as her the second he steps into the throne room, despite his gem being covered by his shirt. Even Blue Diamond and Yellow Diamond did not recognize Steven as Pink until he was able to project her aura during their fight in "Reunited".
- Ivor The Engine: Jones the Steam and Ivor have a very close bond after so many years working together, but Jones usually acts as a sort of parental figure for Ivor, who is good-hearted if sometimes a little disobedient, like a child. Jones can usually guess at Ivors moods quite easily.
- In many instances in the animal kingdom, a mother knows her offspring by their scent. The inverse is true as well, with animal babies identifying their mother the same way.
- Some animal species accomplish this via sound.
- Another example, which also appears under Flags of Our Fathers: The mother of one the Marines who raised the famed flag over Iwo Jima recognized her son in the picture - from the back. She knew her own child's back and buttocks well enough that she insisted it was him even though officially, it wasn't. Eventually, she turned out to be right.