Professor Utonium: Well, what can I say?
Robin: Don't worry, Professor. I was an accident, too!
[The professor's eyes bulge in shock]
Robin: [later] Your dad is funny.
A child was born, who wasn't supposed to be born; this is due to many different factors. Whatever the cause and effect, there is one thing that is for sure: the child is a "mistake", and more often than not, that child is painfully made aware of that fact. If the child takes it bad, could eventually leads to Bastard Bastard, Betrayal by Offspring and even Self-Made Orphan in the worst of the cases.
Compare Surprise Pregnancy, in which the offspring is not necessarily considered a "mistake" (but also overlaps this), and That Thing Is Not My Child!, in which the "mistake" is negated by one (or both) of the parents. Contrast The Baby Trap, in which the "mistake" is made with the main purpose of And Now You Must Marry Me. See also Teen Pregnancy and But We Used a Condom.
- An Alvin and the Chipmunks fanfiction actually sheds light on this, as Jeanette befriends a new chipmunk girl in school named Amanda, who comes from a very abusive home, and even tells Jeanette that her parents constantly tell her, to her face, that she was never meant to be born, and that she is a mistake.
- Downplayed in A Good Compromise. In an emotional moment prompted by the description of a five-year-old boy infected with the Teplan blight, Tyria Sark describes the conception of her daughter Sameen as "selfish" due to conveniently neglecting her contraception while honeymooning with her husband. The implication is not that she actually thinks Sameen was a mistake, but rather that she thinks she shouldn't have impulsively brought a child into that kind of world.
- Inverted in Ratatouille, when one realizes that Linguini is essentially the illegitimate son of famed chef August Gusteau; a letter from Linguini's deceased mother to Chef Skinner (Gusteau's former Sous-Chef, now owner of the restaurant) even admits that Linguini was born of the results of an affair between them, and begs for him not to reveal the information.
- Inverted in Elf, when one considers that Buddy was the result of a brief high school romance between Walter Hobbs and his high school sweetheart, Susan Wells; Susan became pregnant with the baby, never told Walter, and put the baby up for adoption after he was born. Even when Buddy sets out in search for Walter, and DNA tests confirm he's his son, Walter isn't, at first, willing to embrace Buddy, or acknowledge that he is, indeed, his son.
- Knocked Up: A girl gets knocked up after a One Night Stand.
- In the Film of the Book version of Matilda, Mr Wormwood describes himself as being the father to 'one son, and one mistake'.
- In Pirate Radio, Carl explains to his bunkmate how he came to be: "My mom had sex with my dad, and then he left."
- Juno: When Minnesota teenager Juno MacGuff conceives a child with her insolvent boyfriend, she nearly terminates the pregnancy. However, having second thoughts, Juno finds a childless couple in the personal ads, and offers to gestate and birth the child for them to adopt.
- In Everybody Loves Raymond, Robert was always told he was born three months prematurely, but at one point in the series, both Marie and Frank confess they gave into temptation, Marie got pregnant, and they got married to "right the wrong"; Robert being born prematurely was a story they both made up to hide the fact that they engaged in premarital sex.
- In Frasier, Martin tells Frasier at one point, "I wasn't the one who convinced your mother to marry me; you were."
- In Grounded for Life this is why the parents are "grounded" for life - they had sex in high school, she got pregnant, they had to get married. Another see also: Teen Pregnancy.
- Hey, Vern! It's My Family Album! parodies this in a segment about Ernest's mean Uncle Lloyd Worrell, who has a dimwitted son, whose name actually is Mistake, and even unsuccessfully tries to mess with Mistake's mind with psychological torment.
- In the Backstory of Married... with Children, Al & Peg got married because Al impregnated Peg with (what turned out to be) Kelly.
- In other episodes, Al has clearly stated that Bud was also an accident.
- Thea Queen is the love child of Moira Queen and Malcolm Merlyn, conceived while Moira was married to Robert Queen and Malcolm to his wife Rebecca. Thea's heritage is hidden from everyone for over two decades until Malcolm spills the beans following the death of his son, Tommy, his only legitimate heir. By this time, Moira and Malcolm are bitter enemies and Moira describes the affair as a one time slip of judgment, which means Thea was almost certainly a mistake.
- Present-day Oliver loves his son William and would die for him. However, in season 2, we see a flashback where an in-his-early-twenties Oliver is completely freaked out after finding out his long-term fling, Samantha, is pregnant. He literally goes crying to his mother insisting he's too young to be a father and he doesn't want a baby.
- In an episode of Malcolm in the Middle, Lois and Hal are fighting because he lied about getting a vasectomy years earlier, which led to Lois being currently pregnant with their fifth son, Jamie. When Hal tries to counter her argument on him needing a vasectomy, she fires back that they have a "rhythm child," a "diaphragm child," a "condom child," and "two abstinence children."
- During the epilogue of the final episode, after Reese moved in with Craig, and Malcolm went off to Harvard, Hal is telling Lois how happy he his that they only have to wait until Dewey and Jamie grow up and move out so that they can finally be alone. Lois then shows him positive pregnancy test, and Hal lest out a Big "NO!".
- In the That '70s Showepisode where Hyde's mom is introduced as the school's cafeteria lady during "career day," Fez sees her and Hyde get into another argument about how getting pregnant with him led to her abandoning a career as a professional water skier.
- Vaporwave artist Blank Banshee has a song called "Teen Pregnancy", which the only words in the song are "I'm just a kid" and "I'm just a little mistake." This was confirmed by Simpsonwave music video by Lucien Hughes, in which the song is starred by Bart Simpson using various "flashback" chapters in which appears that Bart was a mistake, just like in those referenced episodes.
- Stand Still, Stay Silent: Reynir suspects to have been "a mistake" because all four of his older siblings are proto-Designer Babies, while he's very obviously the natural child of his parents.
- Joueur du Grenier: During Fred's playthrough of Beat Takeshi (one level of which requires the protagonist to beat the crap out of his wife and children), the live reenactment has Fred kicking one of the kids while yelling "Die you fucking genetic mistake!"
- The Most Popular Girls in School: In Episode 24, Mrs. Van Buren tells her three quarreling daughters that they're all "lovely, accidental treasures. Mistakes... but treasures."
- The Simpsons
- Bart was a mistake, as can be seen from Flashback episodes. Lisa & Maggie weren't planned, either, but Bart was conceived before Homer & Marge decided to get married.
- During an argument between Homer and Grandpa, Abe blurts out that Homer was an accident.
- On a later episode, Marge considers having another child, and Homer incredulously responds, "An on-purpose baby?"
- The Powerpuff Girls
- Powerpuff Girls are born by a mistake of Professor Utonium, since he wanted to created a single girl as her daughter, but then the Chemical X was added by mistake, giving birth to three little superheroines.
- Also, various supervillains are born by mistake in the series, prominently PPG's Arch-Enemy, Mojo Jojo, who also has an accident with the Chemical X, transforming him from a normal monkey to an uplifted maniac mastermind.
- In the season 4 episode "Superfriends" appears Robin Snyder, a new neighbor that moves in next door to the girls and befriends them. While she is introduced to the professor, there's a (un)noticeable moment with an uncomfortable conversation.
- Family Guy: Across numerous episodes throughout the series, it is revealed that all three of the Griffin children were mistakes. Chris in particular was due to a condom break, for which the subsequent lawsuit paid for their house.
- In Rick and Morty, Jerry and Beth only got married because they accidentally conceived Summer when they were teenagers.
- In Bojack Horseman, Bojack was conceived when his upper-class mother had an ill-advised fling with a literal workhorse. She has never let Bojack forget this.
- Fairly Oddparents has this exchange:
Dad: My dreams were shattered years ago.Timmy: How many years ago?Dad: Uh... How old are you?