In JoJo's Bizarre Adventure: Stone Ocean, a mother whose new-born died after birth swap hers for a living child... in the process splitting up two fraternal twins. This comes back in the end, when the sibling relationship is revealed.
The final arc of Kinnikuman revolves around the revelation that there was a fire in the hospital on the day the prince of Planet Kinniku was born — and in the confusion he may have been switched with any one of five other newborn boys. A tournament between the six now-grown possible princes is organized to determine the real deal; as it turns out the Kinnikuman we're familiar with, Suguru, was the real prince all along.
Black Jack gives us the chapter "Switched". A mother is blackmailed by a particularly unpleasant woman, who claims to have seen her switch her baby with another one in the maternity ward shortly after discovering that her son had a rare, most likely terminal condition. Once she can no longer make the payments, the mother allows her blackmailer to accuse her of kidnapping. The key witness is Dr. Black Jack, who reveals that it's a subversion - he states that he operated on the child, curing his condition, and that the scar on the child is proof that he belongs to his mother. On the way out, he informs the the blackmailer that after the operation, he saw the child's unknowing mother switch the babies... and switched them back.
Invincible heroine Atom Eve has this as her backstory. The scientist in charge of the Super Soldier project that created Eve felt guilty about condemning the unborn Eve to life as a lab experiment and had her Switched at Birth with a stillborn child. The parents were initially surprised to see Eve after being told their baby hadn't survived, but quickly decided it wasn't important — their daughter was alive and that was all that mattered.
The Flash: It was retconned that Barry Allen had a twin brother who was believed stillborn; however, the doctor actually switched his twin with another couple's dead baby to keep them from pressing charges for botching the delivery, and he was raised as Malcolm Thawne. When Malcolm realized this was one of the reasons for his terrible childhood, he killed the doctor in a rage, demanding to know why he was the one to be taken.
The last part of the prologue of the Usagi Yojimbo "Grass-Cutter" arc mentions a daimyo who, according to legend, was the result of his grandmother switching her actual granddaughter for the son of an umbrella merchant so their domain would have a male heir. As his cowardice brings ruin to his land, the old woman, preparing to sacrifice the emperor's child to keep him from falling into enemy hands, tells the empress that the story was true.
The original sprawling story of "Beauty and the Beast" used this in Beauty's case; her (fairy) mother exchanged her as an infant with the merchant's dead daughter. In the grand reveal at the end, she learns of her noble birth and first-cousin relationship to the former Beast.
Films — Animated
This happens in The Princess and the Pea. Daria (the princess) was switched by Laird with his daughter, Hildegard, so that he could get his vengeance on his brother, Heath. Part of Laird's plan was to pretend that their baby died shortly after birth so that his wife could help raise their daughter to grow up into a Royal Brat. Meanwhile, Daria was sent to live with pig farmer peasants.
Films — Live-Action
A similar theme is used in the 1988 film Big Business with Lilly Tomlin and Bette Midler playing the mismatched sets of twins - each named Rose (Tomlin) and Sadie (Midler) - of a rural working family and a wealthy urban family. Unusually, in the end neither birth nor upbringing turns out to provide the stronger link between the women; instead, urban Rose and country Sadie are Wide Eyed Idealists while country Rose and urban Sadie are aggressive and cynical.
The very same year, French black comedy La vie est un long fleuve tranquille mixed this theme with Slobs Versus Snobs. On Christmas Eve, as she was rejected by her married OB-GYN lover, a midwife switched two babies born that night, a white-trash girl and a well-bred boy. After a final betrayal, twelve years later, the midwife reveals the ugly truth, and the boy comes to live with his rightful family. But as he was raised within a family of crass thieves - but loving ones anyway -, soon, the kid teaches his wealthy parents they should have thought about it twice before taking him back...
Parodied in the film Delirious, where a man trapped inside a soap opera is outraged with the changes its current head writer is making. One of them is the show's idealistic heroine being revealed to have been switched at birth with the daughter of the rich villainous family that runs the whole town, causing her to INSTANTLY become exactly like them.
The Omen began with an swap between a dead baby and a mysterious newborn.
The most mind-hurting example is in the 1970 movie Start The Revolution Without Me. In pre-Revolutionary France, two sets of identical twins are born on the same night and delivered by the same doctor, so there are four babies. The midwife and doctor can't remember which is which, so they shuffle them a bit so "at least we'll be half right". They grow up as two sets of fraternal twins, one aristocratic, one revolutionary peasant. Then the French Revolution comes around ...
This is pretty bizarre, and seems to relate to the belief that nature always trumps nurture, as seen mostly on cop shows.
To be fair, they had to deal with three babies, not two; "a golden-haired male baby we will call Baby A," "a golden-haired male baby we will call Baby B," and "a golden-haired male baby we will call the Adversary, Destroyer of Kings, Angel of the Bottomless Pit, Great Beast that is called Dragon, Prince of This World, Father of Lies, Spawn of Satan, and Lord of Darkness".
This is part of the plot of Mark Twain's novel Pudd'nhead Wilson, involving two sons of a white plantation owner, one by his wife and one by a slave woman, being switched at birth by the slave so her son could live a life of privilege. The titular Wilson finds out almost twenty years later, when he takes the defense of an Italian man (himself a twin) who has been mistakenly accused of murder — and the slave's son is the culprit. In the end, after Wilson reveals the whole switch to save his client, the slave's son is formally enslaved and sold down the river, and the wife's kid is brought back into the family... but he's a Fish out of Water and not happy about it.
In "Lady Clare," a lengthy poem by Alfred, Lord Tennyson, the titular noblewoman discovers that her nursemaid Alice is actually her biological mother, who had been the nursemaid of the real Lady Clare. When the earl's daughter died, Alice switched the infants and claimed the dead baby as her own so as not to deprive the noble family of their only child.
In Andre Norton's Jargoon Pard, Kethan is switched at birth for a woman's daughter, because only a son can inherit. At the climax, this is revealed to the woman and his parents; they reveal that actually, they knew it for a long time. Kethan nearly despairs because his purported mother no longer wants him, because she can no longer use him. After the fight, however, his parents eagerly lay claim both to their biological son and the daughter they raised.
As was the protagonist of Roger Zelazny's Madwand. In the end the two changelings end up making war on each other.
The fantasy novel Split Heirs involves a royal set of boy/girl triplets, where the girl, and younger boy triplet were supposed to be secretly sent off to be raised by the queens brother, while the firstborn boy was to be raised to be the heir to a warrior kingdom. A mix up occurs, and the girl is raised as a prince, and becomes a fearsome warrior, while one boy becomes a shepherd, and the other a wizard's apprentice. The culture of the story thought that multiple births meant the queen had been unfaithful, which would have meant her execution. Also, a girl would not have been able to inherit the throne, so the queen kept the girl's sex a secret even to the girl herself.
A lot of baby-shuffling occurs in Septimus Heap. The title character is pronounced dead at birth by the midwife, but she actually steals him and he ends up getting switched with her own son. Meanwhile, Septimus' father finds an abandoned baby girl, and since his wife is known to have been pregnant and they think their baby is dead, they adopt the girl and pretend she's their own daughter.
In L. M. Montgomery's Anne of Green Gables series (Anne of Ingleside), a mean little girl convinces one of Anne and Gilbert's twin daughters, Nan, that she was switched at birth with a fisherman's daughter. The girl insists that twins always look alike, and the fact that Nan and her twin Di don't, being fraternal twins, it proves that they were switched at birth. Nan does the honorable thing and tries to switch back, only to be told by the fisherman's wife that her daughter is nearly a year older than she is, and therefore they could not have been switched. Quite relieved, Nan turns to go home and gets caught in a storm before returning safely. Anne and Gilbert are understandably upset.
At least two instances in A Song of Ice and Fire. In A Feast for Crows, Mance Rayder's son is switched with Gilly's son in order to prevent Melisandre from taking advantage of his "royal blood" as a sacrifice to R'hllor. A Dance with Dragons reveals that Aegon Targaryen is still alive because of a baby swap.
The Norse Tale of Geirmund Heljarskin has a queen swap her babies with her slave's child.
In the Brazilian Soap OperaPor Amor, a mother switched her newborn for the dead baby of her first daughter. The mother did it in order to relieve the bad news that her daughter became sterile through her difficult birthing. When the daughter, the daughter's husband, and the mother's husband (the baby's father) found out, they were less than pleased.
An episode of Dinosaurs revolved around the possibility that Baby Sinclair had been Switched At BirthLaying. It's heavily implied that this is in fact the case (the other baby is even green, like the rest of the family) but of course he ends up remaining with the Sinclair family.
Home and Away where we learn Jade was accidently swapped with another baby, who turns out to be identical to Jade's (previously though to be) fraternal twin Kirsty
On Road To Avonlea (broadcast in the U.S. as simply "Avonlea"), Felicity and her friend Sally were born on the same day with the same flighty doctor present. When they harass her about not having a mother, Sarah forges a letter from the doctor confessing to switching the babies by accident. Aunt Hetty catches on, but first suggests that they switch the girls back, since the mothers had earlier made a big point of her not being able to understand motherhood, having never given birth.
Veronica Mars contains an example. Veronica discovers that her friend Mac was switched at birth with Madison Sinclair.
One Life to Live is the baby switch headquarters of American soaps. In the early 80s, Karen Wolek switched her sister's dead baby for a living one, a switch that went on for years. Later, Gabrielle switched Alicia's dead baby with Brenda's living son. In 2004, a major Cross Over with All My Children saw Kelly from OLTL raising the child of Babe from AMC, who in turn had best friend Bianca's baby. The most recent involves Bess, an alternate personality of Jessica, who switched Jessica's dead baby for Starr's.
Happened in an episode of Ghost Whisperer, where the ghost of the week discovers she'd been switched at birth shortly after her death, and plans to tell the girl she was switched with, despite both their parents not wanting her to know.
This trope is what prevents straight Brother-Sister Incest in the Korean drama Autumn In My Heart: the main couple were raised as biological siblings, and in their teenage years, when their feelings become muddy, it's revealed that she was inadvertently exchanged with another baby girl because her older brother, a toddler back then, entered in the nursery and exchanged the name tags.
Done on Neighbours when Bree is revealed to have been switched with another baby at birth.
On The Dick Van Dyke Show episode "That's My Boy?!" Rob was convinced that Richie had been switched with another baby at the hospital, because the the hospital kept confusing Richie Petrie with Richie Peters (delivering the wrong flowers etc.) and baby Richie didn't look like either parent. That is, until he met the Peters family, who were black resulting in one of the longest laughs in TV history.
Rob Petrie: Why didn't you tell me on the phone?
Mr. Peters: And miss the expression on your face? He's played by Greg Morris, later known for his work as Barney Collier on Mission: Impossible.
The end scenes had Rob say the Peters' son, Jimmy is a straight-A top student, while Richie...isn't. He then insists, "I still think we got the wrong kid!" Laura playfully hits him with a sofa pillow.
Castle has an episode where two babies were switched at birth because one of the fathers knew that his child had an always-fatal hereditary disease.
Gilbert and Sullivan used (and parodied) this one frequently; it shows up in H.M.S. Pinafore (where the heroine's boyfriend is revealed to have been switched with her father, who in turn goes on to marry his former wet-nurse) and The Gondoliers (which actually involves multiple switches).
This was a major story point in Shadow Of Destiny, where the two female characters in the game (one from the past, one from the present) turned out to have been switched at birth by the "Homunculus" as part of his scheme to ensure that history turns out exactly as he wants it to.
In Tales of the Abyss, it turns out that Natalia was actually not the blood princess of Kimlasca—the real princess was stillborn, and the midwife switched the infant with her daughter's child. To make matters worse, her real father was one of the Six God Generals, Largo the Black Lion.
In Umineko no Naku Koro ni, Rudolf Ushiromiya switched the babies of his wife, whose child was stillborn, and his mistress, and the child would grow up to be his son Battler. For years Rudolf was the only one who knew about this.
Hatoful Boyfriend has Sakuya, though it's not "switched" so much as "replaced". His brother Yuuya was supposed to kill him in the egg, but held on to him, switched his egg with his purebred half-brother's, and smashed that.
Modern, western hospitals go through extraordinary measures to prevent this from happening, after some well-publicized (and very expensive) cases that came to light with the advent of DNA testing.
In Russia, it recently happened to two infants girls. The families still see each others frequently, and the girls still say "Mama"! when they see the other's family mother. Who miss them actually.
In Beyond Belief Fact Or Fiction, this story was introduced as true: A woman discovered, thanks to her premarital exam, that her blood group wasn't like her parents'. She came to the hospital with her fiancÚ who was born the same day and at the same place on a confusing night (New Year's Eve, during a tempest). The mess led the nurses to write the wrong sex on minute books. So she was switched at birth, with her own future husband, no less.
Believable if you consider the fact that people tend to marry those who remind them of their parents, and who better to remind you of Daddy than his own son, and of Mommy than her own daughter?
As mentioned under Film, this happened to Kimberly Mays and Arlena Twigg which inspired the aformentioned TV film Switched at Birth.
Brood parasitism is a strategy used by certain bird species, most famously the Common Cuckoo, as well as some species of bee and wasps.
This is a darker variant of this trope since there isn't any actual "switching" involved. The cuckoo chick simply hatches earlier than the other eggs (cuckoos incubate their eggs in their bodies longer than other birds to make sure this happens) and pushes the other eggs out of the nest to their doom. This strategy only works because most birds are too stupid to tell the difference between a chick of their species and a cuckoo chick (who is sometimes larger than the "parents"). If the parents are smart enough to ditch the cuckoo chick, a bunch of adult cuckoos attack them according to what is seriously called the "Cuckoo Mafia Theory". Cuckoos are creepy.
This seems even more cruel when you consider that since cuckoo chicks are even larger than the "parents" much of the time, the "parents" struggle to get enough food to feed it.
Some cuckoos don't push out the other eggs, but they're generally larger and stronger-voiced than their hosts' chicks, so they get fed more and are often the only ones that make it.
Interestingly enough, humans trying to save an endangered bird species will do something similar to this. A bird species that very nearly went extinct would only lay and watch one egg at a time, but if the egg was removed, it would lay another egg. So conservationists would take the egg from the endangered bird, and put it in the nest of another bird of similar size and diet. Said bird will raise the chick as it's own. This technique saved a bird species from extinction, with literally only a few specimens to start with, the population is now at a few hundred.
This was done with the California Condor. A lot of the extra chicks were raised by life-sized condor puppets so they would imprint correctly.
The rare whooping cranes' eggs, one or maybe two at a time, were put in the nests of the common sandhill cranes. The whooping cranes laid more eggs, the transplanted chicks were raised by the sandhills, and the numbers went up.
Inverted in the case of Patricia Noonan and Shawn Lake, two similar-looking teen girls who were involved in a car crash. Lake died and Noonan was in a coma; Noonan's parents were informed that their daughter had died and Lake's that theirs was in a coma.
A similar case happened with Laura Van Ryn and Whitney Cerak in 2006. After a horrific car accident, Whitney and Laura were misidentified and the mix-up was not discovered for five weeks. Whitney Cerak was believed dead, and was alive; Laura Van Ryn's family had thought that the girl they had cared for was actually Whitney. A book, Mistaken Identity, was written about the event.