Guinea Pig Family

(Mad) Scientists have a recurring problem when it comes to finding human test subjects. But rather than kidnap people off the street, or experiment on himself, he chooses to use his family as guinea pigs.

Maybe it's because family members, having grown up on stories of his science, are easily convinced to volunteer. Perhaps they are The Caretaker of an Ill Girl (or spouse) and the whole point of his experiments is to find a cure. Or most horrifying of all, he decides that big bro is expendable, or he can make more of Timmy the old fashioned way (cloning, of course!) For some reason, most scientists rarely use their parents as test subjects, though such testing can travel down family lines as a tradition.

The results run the gamut. The family member may be given super powers, cured of an illness, mutated into a horrible monster, or killed (this last one will generally turn a normal scientist into the mad variety). Depending on circumstances they may also turn evil or stay good, and if their family member is of the opposite alignment they might rebel. If this testing is done to more than one family member, it becomes a natural evolution to Secret Project Refugee Family (sometimes without the Refugee part).

Anime and Manga

 * Fullmetal Alchemist Poor  Shou became a Complete Monster right then and there.
 * One of Rumiko Takahashi's short stories involved a boy whose parents kept experimenting on him as part of their 'get rich quick' schemes.
 * Baccano's Chane Laforet was actually born as the result of an experiment -- namely, her Mad Scientist father Huey was curious as to whether or not his immortality could be inherited. It's not exactly known if he continues to experiment on her (besides the obvious emotional manipulation), but Huey does refer to her as a guinea pig on a regular basis.
 * Franken Fran has Fran turn her "little sister" Veronica into one of these over their differing opinions on life (i.e. Veronica thinks it's better to let someone die than subject them to a Fate Worse Than Death).
 * Poor, poor Crona. Mom's Moral Event Horizon got crossed when she used you for her black blood experiments, didn't it?
 * Bleach: Mayuri Kurotsuchi didn't have a family to use as guinea pigs, so he made one. This doesn't stop him from grabbing unwilling test subjects, but it seems that his two favorite things to experiment on are his daughter and himself.
 * Not his family, but Mayuri's (less) Evil Counterpart in the Espada, Syazel Apporo Granz, modified and created his Fraccion (Mooks) so that, if he was injured, they can regenerate him...by eating them. However, Szayel does play this straight--he has an older brother, Yylfordt, whom Szayel conducted his research on without Yylfordt knowing. Of these, Szayel seems most proud of surveillance bugs placed inside Yylfordt to where Szayel refers to his brother as a "box" that was opened through his death.
 * To Aru Kagaku no Railgun reveals  as the subject of experiments by her grandfather.
 * Professor Watabe of Psychic Academy treats his daughter Mew like this. It's so extreme that he never bothered to name her: Mew Baurra is the first two pieces of her Aura Code, not an actual name. She is technically nameless until Ai arbitrarily gives her a name... when she's about 16. Watabe's experiments grant her considerable power - at the cost of her powers being uncontrollable while in certain mental states, capable of damaging her own health if she uses them too much, and the sprinklers that went off whenever she lost control during experiments and set the room on fire gave her a crippling fear of rain.
 * The Code Geass novels seem to take this route, a bit:  are a result of experimentation with Geass while she was in the womb, and her   was an attempt to get her to use those abilities. For the record, they seem to be   Considering the number of elements added to the second series from other spin-offs - specifically, Lost Colour's Knight Of Nine, and Cornelia's two wing-girls who join the Valkyrie squadron after her disappearance - it's not completely impossible that it was added into the background. Just look through the two seasons and count how often   seems to be able to detect something that she shouldn't really be able to.
 * Fanfiction also sometimes takes the route of certain Imperial Family members unusual hair colours being a result of basic genetic modification. Even if it's gotten to the point where no one really questions pink and purple hair, it's nice for it to make sense every now and again.
 * Cyborg 009's Ivan Whiskey was experimented on by his father Gamo and turned into Cyborg 001, a powerful psychic. Because he was converted into a cyborg when he was just a few months old, he'll be stuck in the body of an infant forever. This is also a case of.
 * If one includes the 2007 adaptation of Skull Man, then, though neither is aware of this.

Comic Books

 * Fantastic Four: By accident, though.
 * One of the origin stories from Batman's Mr Freeze had him experimenting cryogeny on this ill wife to keep her alive until a cure was found of her illness. It could have worked, if not for outer influence.
 * Timberwolf of DC Comics Legion of Super-Heroes.
 * Mimic, an early X-Men villain got his powers either a.) his father experimenting on him to develop superpowers or b.) his father experimenting on him to activate his mutant powers.
 * Vandal Savage, an immortal cro-magnon, sires children so that he can later harvest their organs. He's immortal, but not invincible.

Film

 * Repo! The Genetic Opera has the Repo Man try to save his wife this way... she dies.
 * In the 2003 Hulk film, Bruce's origin story is expanded upon: the Freak Lab Accident doesn't give him super-powers by itself, but triggers a mutation caused by his father experimenting on him when he was a baby. There was also some overlap with Professor Guinea Pig, as his father had initially been experimenting on himself, and some of the resulting mutations were passed on to Bruce.
 * In the backstory to Scanners, Dr. Paul Ruth created a tranquilizer drug for pregnant women, and the first test subject was his own pregnant wife. Everything seemed to be okay, so he put the drug into circulation, and they used it again the second time she got pregnant. Little did Ruth realize, it created a Bizarre Baby Boom, of which his own sons were the most bizarre.
 * In the horror film Manster, it's revealed that besides the American journalist, the Mad Scientist used as his first experiments.
 * The scientist Will Rodman in Rise of the Planet of the Apes uses an experimental drug on his father, who has Alzheimer's.

Literature

 * The novel Killing Time by Caleb Carr has an example of this trope.
 * In John Wyndham's Trouble with Lichen, a scientist who has created an anti-aging drug uses it on his children, telling them it's a vitamin shot.
 * The novel Gladiator explores some of the consequences of this trope.
 * In the Petaybee series, the Shongilis. Apparently Granddaddy Shongili meddled enough with his own genetics to produce at least one selkie (Sean) a few generations later. Sean's kids are natural-born selkies as well.
 * In James Patterson's Maximum Ride,
 * In This Immortal by Roger Zelazny, the Absent-Minded Professor borderline Evilutionary Biologist (he euthanized the last dog on earth) George Emmet wanted to experiment on his children...but his wife put her foot down.

Live Action TV

 * The Twilight Zone TOS episode "Mute". Two parents make their daughter the subject of an experiment: to induce telepathic ability in her by never speaking to her.
 * Simon and River Tam of Firefly are a more benign version of this as it was part of being The Caretaker and of course she knew perfectly well that he would have to learn on the job because getting outside help was impossible, and he obviously hated it very much. One hesitates to put this here as it was clearly not the same sort of thing as the more sinister examples and there were no other options. But the description above does say that this would fit.
 * Kevin Fawkes implants the Quicksilver gland in his brother Darien's head, turning Darien into the Invisible Man.
 * On Lost, Juliet tests her fertility research on her sister Rachel, who is infertile due to chemotherapy. It pays off for Rachel, though, when the research works and she ends up getting the baby she always wanted.
 * In an early episode of Fringe, it was strongly implied that Walter experimented on his son Peter as a child though this hasn't been revisited since.
 * In Two and A Half Men, Walden's mother Robin, a primatologist, raised Walden and a baby gorilla at the same time as an experiment, even going so far as to freeze Walden's embryo to make sure he and the gorilla were born at the same time. Walden does not take the revelation well; he thought "Magilla" was an imaginary friend, and was so traumatized when the gorilla was taken away that he believed he would be sent to the jungle if he misbehaved. All things considered, Walden turned out relatively well, and as Alan points out, compared to his own mother, Robin was Mother of the Year.

Video Games

 * The fact that in Final Fantasy VII. Sephiroth was implanted with Jenova cells while still in the womb by his father, Hojo, definitely counts. Things went badly.
 * Caulder/Stolos' family in Advance Wars: Days of Ruin were an experiment in human cloning, and his son Cyrus a (scrapped) Guinea Pig for Grand Theft Me on top of it.
 * The remake of Resident Evil added Lisa Trevor. Her father George Trevor was the architect who designed the Arklay mansion. When he discovers the mansion true purpose he is killed by Spencer and kidnaps his wife and daughter to be used as guinea pigs for Umbrella's viral experiments
 * Heinrich von Raitenau in Trauma Center: Under The Knife 2 uses his own children as Sinners: Living incubators for the man-made pathogen GUILT.
 * Played with in Star Ocean Till the End of Time. Fayt and Maria were experimented on by their parents and subsequently given reality bending superpowers. Their parents are not malicious in nature however, as they were trying to give them the abilities to save the universe from being destroyed. They also explicitly state that they used their own children as they felt it would be wrong to ask another person's child to shoulder their sins.
 * Relius Clover from Blaz Blue turned his daughter into a mechanical super weapon and then used the data to turn his wife into an even more powerful machine.
 * Aperture Science eventually resorted to using its own employees as test subjects, not because of any malicious intent, but simply because its star had fallen so low that it was barely hovering above sea level. And this was after a period where they used homeless people off the street.
 * That's because when they were using hobos, they were still paying their test subjects (Sixty bucks a head, and a whole twenty minutes in the breakroom if you survive the test! Wow!). Whether or not the employees are still getting paid or if they're just under some kind of contractual obligation whether the paycheck is coming in or not isn't made clear. It does explicitly mention that the CEO isn't exempt; he's the guy who got to discover that if you grind moon rocks into powder and put it in Mobility Gel base, it's poisonous.

Western Animation

 * This is the central premise of Johnny Test, with far more Snap Backs than usual for the trope.
 * Richard Impossible of The Venture Brothers at the very least uses his brother in law, whose skin ignites in fire when in contact with air as a power source. Also Dr. Venture uses his sons basically as walking organ banks and had dozens of clones of them, until all the clones were destroyed.
 * This is the explanation Dr. Paradigm gives as to how the Street Sharks came about - that their evil scientist father mutated them into shark/human hybrids. Subverted in that the heroes all know full well that Paradigm was the one who mutated them.

Real Life

 * Not uncommon for researchers in such areas as child psychology and child language acquisition. (They may also acquire experiment subjects otherwise and add the researchers' own offspring to boost the sample size, as some researches require large groups and control groups.) Of course, truth is usually less scary than fiction (although human experimentation in these fields of study isn't always harmless).
 * Not For Science!, but Munchausen-by-proxy in action tends to look like this; a parent fakes or induces illness in their child for attention ("Look at me and my sick kid!").