The acquisition of superpowers or abilities at the onset of becoming a teenager, roughly between the ages of 12-16. This is probably to avoid the inherent danger of a child or baby casually using powers in a potentially destructive manner or, if there is one, blowing the Masquerade. However, more often, it works as a rather transparent metaphor for puberty.
Curiously, few such teens have trouble figuring out How Do I Shot Web?; apparently, the powers are just instinctive. This doesn't stop mentor figures from putting them through Training from Hell to master those abilities, however.
Nearly all current "dramatic" superheroes with "natural" superpowers (such as Marvel's mutants) receive them as teenagers. In fact, the trope originated with the creation of the X-Men in the 1960s.
This in turn was possibly influenced by the folklore about poltergeist manifestations being associated with adolescents, which in turn has been interpreted as a metaphor for sexual awakening.
See also Dangerous Sixteenth Birthday. Compare The Call Put Me On Hold.
Contrast Growing Up Sucks where a character possesses a power throughout childhood, but loses it at puberty instead.
The age is thirteen in Mermaid Melody Pichi Pichi Pitch. Any mermaid with her pearl becomes a legal adult in the mermaid world, as well as summoning an apparition of Aqua Regina, who may or may not upgrade her power.
In Karin, vampires are born outwardly normal and attend school like anyone else until their vampirism suddenly kicks in and they become weak against sunlight and so forth, which can happen any time up to high school.
Omamori Himari: Yuuto's demon-hunting powers were supposed to have awakened when he turned 16. His powers took a little longer to manifest, however.
Haruhi Suzumiya gained her reality-warping abilities at age twelve. Itsuki got his Psychic Powers at the same age, though in his case it wasn't a real example since he got his powers because of Haruhi subconsciously creating espers, and he just happened to be around the same age as her.
X-Men: As mentioned above, this franchise is very much the Trope Maker. Mutant powers usually manifest at puberty. This happens on birthdays more often than is statistically warranted.
The X-Men spin-off 'New Mutants' is explicitly this trope; all team members have powers that appeared with puberty, a varying number of years in the past (Xian's the longest ago (she's 19), Rahne's only a month or two before (at 13)).
Generation X is about a group of powered teens at Xavier's spin-off school.
Exceptions to the Puberty Superpower tend be extreme. The shapeshifter Morph, as explained in Exiles, was born a fairly squishy mass of a baby. Nonetheless he counts himself lucky, since his power allowed him to quickly shift into a more normal appearance and live a fairly happy family life.
This is also very similar to what happened to Captain Britain's girlfriend and later wife, Meggan.
There is also Jamie Madrox aka. Multiple Man, whose mutation showed itself directly after birth when he created several copies of himself after getting the usual slap on the behind. Under writer Peter David, it's been suggested that mutants-who-manifest-at-birth aren't technically mutants, but rather something mysteriously other.
A fairly mild exception was Hank McCoy alias the Beast, who only had larger than average hands and feet when he was born.
Kurt Wagner alias Nightcrawler was born with the physical characteristics that accompany his teleportation power, i. e. he was born with blue fur, hands and feet with fewer digits, a prehensile tail etc. The teleportation itself was a straight example of this trope.
Franklin Richards is a major Marvel Universe exception who, even more dramatically than Superbaby, shows the dangers of a child who possesses (literally) world-shaping power.
Power Pack is an exception, where the Power siblings gain their powers from an alien, with Alex at 12, Julie at 10, Jack at 8, and Katie at 5 when the comic first started.
Her younger brother Benjamin however turned out to have superstrength and the ability to shoot organic webs as an infant. Luckily, as it turned out, as he was thus able to save his own and his mother's life.
Lampshaded by Molly Hayes in Runaways; when her powers developed, she kept trying to talk to her parents and friends about the weird things her body was doing, but they all thought she was just talking about normal puberty.
Horrifically inverted in the back-story of Billy Butcher from The Boys. After Butcher's wife was raped bya superhero, she dies when the unborn super-powered fetus literally rips itself out of her womb.
Avengers Academy has many of the students manifest their abilities during teenager-dome, in extremely traumatic ways. Jennifer Takeda, for instance, discovers her abilities when making out with her boyfriend. Unfortunately for Jenny, her ability is to project and excrete hazardous, toxic and radioactive materials. He doesn't die, but the trauma haunts her.
Notable film exception: Pixar's The Incredibles, regarding Dash and especially Jack-Jack (who was modelled after Franklin Richards, in keeping with the Fantastic Four references throughout the film). In a DVD extra showing an early opening scene that wasn't used, Violet uses her powers as a baby as well.
Although, of course, Layla said that she used her powers to help her lima bean plant grow back in kindergarten. Perhaps the latest one receives powers in puberty, like 'Up, up and away.'
And to be honest, the film only has the main character as having his powers first activate on-screen whilst he was in his teens, and it does kinda say that what with the powers being in the blood, the Puberty Superpower is the last possible point for you to gain superpowers (unless you have a vat of toxic waste), afterwhich its pointless to have that cape at the ready.
Speaking of, Charlie from Firestarter is an exception, since she showed her abilities in infancy, much to her parents' alarm.
Carrie dealt with this theme. Note that superheroes aren't the only ones with super-powers...
The book however mentions an incident which happened when she was still a baby. So her powers only returned with puberty, apparently.
Not necessarily "returned". Carrie always had the powers, but puberty turned them Up to Eleven.
Similar to the Freudian ideas on human development and sexuality.
Magicians in The Covenant have a two-level Puberty Superpower. They first get their powers around age 13, and get a massive power boost when they hit 21 18.
Justified or Handwaved (your choice). One magician did outright say abusing the power ages you (along with making go insane). One characters father was only about 45 yet looked 100. They're teens with magic. Do the math.
Cruelly averted in Scanners, where the telepaths of the title are quite capable even before birth. This guarantees that when they grow up, they will have a host of psychological problems, and - because they've been able to hear the thoughts of others their whole lives - a deeply flawed sense of self.
The whole point of the Disney movie Up Up And Away, where the middle child of a superhero family is quickly approaching his 14th birthday. All superheros receive their powers before this age. If they don't, then they remain ordinary humans. His younger sister, though, got her Eye Beam powers at the age of two (now imagine for a second a two-year-old who can shoot lasers out of her eyes), so 14 is just a cut-off age. He remains a human at the end but comes to term with it, and his best friend suggests he still becomes a masked hero but without powers. On the upside, he can touch aluminum foil.
In order not to cause his father (a respected local hero named Bronze Eagle) to be embarassed at having a normal son, the kid fakes having superstrength (by rigging a patio door to fly off its hinges when he opens it) and flight (by throwing a ball at a tree and running away). His grandfather (a retired hero named Steel Condor) sees right through him and urges him to tell his father the truth.
Yet another notable (and extreme) exception: In Robin McKinley's Spindle's End (an expansion of the various "Sleeping Beauty" stories) magic permeates everything and the Fairies are actually normal people who just happen to have the inborn ability to control it. Some Fairies come into their power fairly early. A few manifest powers very early, a phenomenon known in the novel as "Baby Magic". As cutesy as that sounds, it's actually very dangerous and unpredictable. A baby Fairy may be able to understand Animal Talk. Or, he may be able to transform the nanny into a terrier and pull a One-Winged Angel act every time he has a tantrum...
Averted in Olaf Stapledon's Odd John, where the title character had special abilities from birth. However, those abilities also came with a cost (including much slower childhood development and physical frailties)
Inverted in A Coming of Age by Timothy Zahn: Children do not develop their telekinetic powers at puberty, but at approximately 5 years of age, however they instead lose their powers at puberty.
But people only begin to achieve their full power at age 100. This emphasises how Bad Ass Harry is, as he isn't even 40 and is among the top 20 most powerful wizards on the planet.
In Mercedes Lackey's novel series, the Heralds Of Valdemar gain their Gifts, and their Companions, in their teen years. It can be traumatic when this happens much earlier or much later than 13 or so.
Played with in her Five Hundred Kingdoms novels, in which those likely to be magic users feel magic growing around them at the point when a fairytale would usually begin in their case, which is usually mid-teens.
Almost every superpower in Women Of The Otherworld is a puberty superpower. Werewolves first begin to change at the end of puberty; the average age of their first change is 18, although it can happen anytime between 15 and 21. Witches can begin practicing minor spells at a young age, but after their first period can perform a ritual that greatly increases their magical strength. Half-demon powers also start showing up at the beginning of puberty, and increase in strength until their late twenties. In fact, the parallel young adult series focuses on adolescents just coming into their powers.
The Firestarter refers to this. The child protagonist already has the titular powers... but scientists are afraid puberty will make them spike to nuclear levels.
The twin sisters in T Witches discover they have magical powers at age 14. In the the movie, it was curiously changed to 21.
In Diane Duane's Young Wizards series, the Powers most often offer Wizardry to kids in their teens; Nita is considered a bit early, at 13, Kit even earlier, at 12, and Dairine is shockingly young at just 10. The younger a wizard is when they start, the more raw power they have; however, the Powers generally want kids to have as much of a childhood as possible before offering them the magic.
They also get a smaller burst of power from hormones during puberty, as happens in High Wizardry: Kit has a growth spurt, and Nita is getting a little bit of growth up top.
In Bras And Broomsticks by Sarah Mlynowski, Rachel Weinstein's younger sister gets magical powers before her. This is explicitly because of puberty; her sister was an "early bloomer".
While Magyk in Septimus Heap manifests itself much earlier than puberty, Apprentices achieve full abilities when they turn 14.
Mostly averted in the novel Starcraft: Ghost: Nova with the titular character who is an extremely-powerful telepath and telekinetic. While, normally, psychic individuals are required to be turned over to the Ghost Academy, Nova is from one of the Old Families of Tarsonis, and her father uses his considerable influence to keep her "gift" hidden. It's mentioned that she's been able to do things from infancy and always appears to know what people are thinking and feeling. However, it's not until she's in her teens that her powers start approaching "critical". When her parents are killed in front of her by a bunch of rebels, she literally goes nuclear, wiping out the rebels and any innocent bystander nearby, as well as shattering the penthouse dome, which is rated for nuclear strikes.
The special children in Supernatural develop their powers at the age of 22 years and six months. Past puberty, but still valid as a metaphor for emerging into adulthood.
Notable exception: Characters in The 4400 were granted superpowers by people from the future at various ages, from childhood to old age. The one in-show exception is Isabelle, who was conceived and implanted into Lily's body during her abduction, and shows extremely powerful abilities as an infant and even some powers while still in the womb. Indeed, the character of Isabelle never really goes through puberty at all, as she is aged from an infant to adulthood in an instant at the end of the second series.
Betazoids (a naturally telepathic race) in Star Trek gain their mind-reading powers at puberty, except for a few rare exceptions who are born telepathic. Those tend to be mentally unstable from not being able to "tune out" the mental noise around them.
Endora brags that Samantha was able to fly on her own by age five, but then adds that Samantha had been precocious for her age.
Sabrina the Teenage Witch claims that half-witches come into their powers on their 16th birthday, before which Sabrina's aunts had engaged in an elaborate Masquerade to keep the other world a secret from her — though this does not jive well with the later implications that witches are generally comically bad at dealing with things in the usual mortal way, and that deliberately avoiding magic is unhealthy for a witch. This is also retconned in Sabrina: The Animated Series, where a 13-year-old Sabrina has full knowledge of the other world.
That or the cartoon was just following the path of the original Sabrina the Teenage Witch comic books, where Sabrina is shown with her powers even as a child (in a few "Little Archie" stories).
Heroes averts this. Characters manifest their powers at various ages. Some, like Nathan Petrelli or Matt Parkman, manifest well into adulthood. Others, like Micah Sanders or Molly Walker, manifest before puberty. The youngest example is Donna, from the comics, who was unaware she had a power at all because she'd had it from birth. She had simply assumed telescopic vision was normal. In fact, the only character confirmed to manifest during the teenage years is Claire Bennet, who manifests at 15.
No, it's made clear that hers has manifested before that, the Haitian's just been wiping her memory. It's implied to be how she survived the fire when she was a baby.
Matt Parkman Jr. is the most outstanding aversion of the series, his "touch and go" power manifest before even his first birthday.
Averted on Merlin - the titular character could use his magic 'before he could talk'.
Spaced: The comic Tim is working on is about an orphaned kid who is exposed to some weird chemical by an amoral 'Doktor' as part of some twisted experiment. Absolutely nothing happened and the Doktor destroyed his research. Then when puberty hit, the dormant chemicals in his bloodstream activated and the orphan kid mutated into the comic's titular Bear.
Slayers in Buffy the Vampire Slayer fit this model too. They suddenly become a Slayer around thirteen or fifteen. Right up until Willow breaks the 'one girl' system in season 7's "Chosen".
Not most of them, prior to Willow's spell at the end of the series. Only a few Potential Slayers ever end up being "activated". Most aren't, and if they're not called by the age of 20 or so, they never will be.
Angel inverts this with Connor in season 5. His new "parents" take him to Wolfram and Hart for help when he discovers his abilities after being hit by a truck and later being able to fight demons. He eventually finds out the truth.
In Smallville, while Clark had super-strength and super-speed as a child, most of his other powers didn't manifest until he was in his teens. In one memorable case, his heat-vision first manifested due to sexual arousal... make of that what you will.
In TheTomorrowPeople, new teeps begin manifesting their powers in a dramatic "breaking out," their head suddeny crowded with overheard voices via telepathy and, more dangerously, teleporting instinctively with no destination in mind, winding up stuck in hyperspace forever. (The revival solves that problem, at least, by means of a beacon which would draw any undirected teleports to a single location, letting them learn how to 'jaunt' safely and bringing them together to learn from each other, like teen girls dragging a friend off to the bathroom to explain the facts of life or deal with an embarassing period accident.)
In both Werewolf: the Apocalypse and Werewolf: the Forsaken, werewolves or other fera/changing breeds generally go through First Change around puberty at the earliest. Depending on circumstances, it can happen significantly later in life, or very rarely earlier. In the New World of Darkness, puberty is also a common time for psychic powers or the more innate forms of thaumaturgy to manifest.
Shigesato Itoi has stated in an interview that this was the way that all the characters with PSI powers gain new abilities throughout MOTHER3.
In Dragon Age, a mage's powers generally begin to manifest at the onset of puberty, though some can and do receive them much earlier.
In Mass Effect, due to biotics being caused by a fetus undergoing Element Zero exposure whilst in-utero, it's possible for newborn infants to manifest biotic abilities at birth, while others remain latent biotics until secondary exposure later in life.
According to Word Of God, all biotic classes of Commander Shepard are the latter, having undergone secondary exposure and subsequently manifested their biotic potential at 17. After joining the Alliance Military a year later, they were then fitted with L3 implants.
Another exception: PS238, which deals with "prodigies", who are elementary-school students with superpowers (one of the titular school's taglines is "PS238: Making sure the next generation doesn't break too much of this generation's stuff").
The Order of the Stick also makes an exception: Xykon, although being a Sorcerer, has his necromantic powers manifesting while still a young boy.
Mutants living in the Global Guardians PBEM Universe generally go through the activation of their powers between ages ten and twelve, with some cases waiting as late as age fourteen.
In the Winds of Change universe, people Change into half human, half animals during puberty. They also gain awesome powers.
The adult fiction series Tim, the Teenage MC both plays this straight and averts it. Tim is born with his telepathic powers switched on, but "grows out of them" shortly after learning to talk. He forgets about them until they reactivate around puberty.
The alien race Starfire of Teen Titans belongs to is born with powers, but undergoes a metamorphosis during the teen years (with puberty metaphor fully in place) that may grant additional abilities.
Danny in Danny Phantom made light that he was gaining "evil puberty" powers once he received the Ghostly Wail. His powers from the beginning onset also reacted to his growing teenage body (example: his nervous emotions towards a girl triggered an unexpected intangibility and cause his pants to fall down, poor poor Danny).
Inverted in Transformers Animated. Sari realizing her robot heritage and upgrading herself with the Allspark key actually causes her to go through puberty. It's never really explained how this works, nor is the disorienting nature of going from eight to a teenager in an instance addressed in any way.
Since Sari is a Cybertronian, it was probably just an upgrade to her body; happens all of the time in Transformers.