You want two of your characters to have a child, but going through a normal pregnancy isn't an option. If the story is Speculative Fiction, the universe's Phlebotinum may be sensitive to the Power of Love or able to generate a new life form by using some kind of contribution from two different people, thus bringing their Phlebotinum child into existence.
Often, the couple can get their child in a much shorter timespan, it can age much faster, or be born mostly grown. As an extra bonus, the child's nature can explain Plot-Relevant Age-Up, Absurdly Youthful Mother, Supernaturally Young Parent, the female variant of Luke, You Are My Father and Homosexual Reproduction. It can also bypass one of the obvious side effects of Can't Have Sex, Ever.
An essential element of this trope is that the Phlebotinum child wouldn't have existed without something from each of its parents combining. The nature of what got combined can include anything that is not the natural conception means of the parents' species.
If more than two people are involved in the child's conception, this trope can be the supernatural counterpart to Extra Parent Conception. Pregnancy will be either absent from the child's generation process or shorter than what would be normal for the mother. In the absence of pregnancy, the parents may have Doorstop Baby-like scenario with the child before finding out the truth. In the latter case, the child may or may not have been generated in a Uterine Replicator or something similar.
These children tend to have a death rate much higher than that of naturally-born children for reasons including Fantastic Racism, being a Living MacGuffin, unable to exist for very long in the first place, or some dangerous form of Sentient Phlebotinum. This makes them a choice character to use in a Parents for a Day scenario. If they live, they will often become an important plot element.
Specific cases can fall into:
- Kid from the Future: You haven't had the child... yet, but they're around anyways.
- Love Imbues Life: In cases where the love is given by two people or more.
- Wonder Child: If natural conception is impossible due to the mother being too old.
- Mix-and-Match Man: In cases where at least one of the parents exists as a separate entity from the child.
- Mystical Pregnancy: The supernatural conception variation.
- That Thing Is Not My Child!: When the parents themselves don't want anything to do with the child.
- Whether Designer Babies and in general Phlebotinum using genetic material that is not sperm and egg can qualify is context-sensitive. If a child born of it is enough of a freak event to qualify as a Plot Point, it falls into this trope. If actual sperm and eggs are used and/or the Phlebotinum is routinely used to produce children, it doesn't qualify. Too much is when people born that way are so frequent that it's considered normal by at least some people In-Universe.
Not to be confused with Bizarre Alien Reproduction, where the reproduction means is strange from a human point of view but normal for fictional beings. Compare Convenient Miscarriage that is the closest non-Speculative Fiction seems to be able to get if the child dies.
Beware of unmarked spoilers.
- Reinforce Zwei in Lyrical Nanoha is a Unison Device, a type of magitek Robot Girl, who was "born" from Hayate's Linker Core (magical "heart"). The "conception" part comes from the fact that Hayate's Linker Core previously merged with that of her late Unison Device, Reinforce Eins, so Zwei bears resemblance to both of her "parents".
- In Sword Art Online, the child-like AI Yui was able to exist in the game's main world thanks to the love Kirito and Asuna have for each other, and considers them her parents. Kirito and Asuna consider her to be their child, but the plot kept her from lasting very long as she ended up making a heroic sacrifice to save them. Also a subversion of the death outcome as her data got saved and got to be restored later on. On an additional note, Kirito and Asuna are both in their mid-teens.
- Technically Alas=Ramus from The Devil Is a Part-Timer! is this for Maou and Emi. She was created from a fragment of Sephirah Yesod (the same thing that made Emi's holy sword) which was given to Maou by Lailah, an angel who was Maou's mentor (and is also Emi's mother).
- In The Avengers Scarlet Witch used magic to get pregnant from her husband The Vision. The magic she had drawn on however turned out to be from a demon who decided to erase her twin sons from existence.
- But now they exist again as Wiccan and Speed of the Young Avengers. Apparently.
- In a Swamp Thing / Hellblazer Crossover, Alec (the Swamp Thing) possesses John Constantine so that he and Abby can have a child. However, Constantine, unbeknownst to Alec, has recently had a transfusion of demon blood. Although Rick Veitch left the title before he could explore the implications of that, the storyline does hint that Alec's and Abby's future child (eventually named Tefé) might end up demonic. The first Vertigo revival of Swamp Thing, centered on the teenaged Tefé, indeed portrays her as a threat to humankind.
- In the My Little Pony: Friendship Is Magic fanfic My Little Mommies, the mane six explore an old mansion that turns out to be an abandoned base of an ancient villain. A mirror enchanted to perform LEGO Genetics, which the villain used to create monstrous hybrids, activates in their presence, mixing genes from each pair of mares and creating 3 female foals for them.
- In the My Little Pony: Friendship Is Magic fanfic Past Sins, an evil cult tries to bring back Nightmare Moon, but ended up giving life to a cute small black alicorn filly that ended on the care of Twilight Sparkle, who ends up adopting her.
- In Frozen, Olaf was originally built by Anna and Elsa as children before being rebuilt by Elsa's powers. While Anna's contribution could be argued to be quite minor compared to Elsa's, the fandom pretty much considers him to be Anna and Elsa's child.
- In A Song of Ice and Fire Daenerys may have been invoking this trope when she decided to hatch her dragons on Drogo's pyre while she was also inside it. Mirri Maz Duur can be considered to be a "third parent" in the process.
- In the Star Trek novel Spock's World, Sarek and Amanda had to rely on Vulcan science to create Spock because Vulcan and human biology are not naturally compatible.
- In The Dresden Files, one way a spirit of intellect can be brought into the world is when a spiritual being and its human host get so close to each other that they experience pure love. Since true love is a force of creation, the remains of the spirit mix up with the host's psyche to produce a new spirit who inherits traits of both parents and is "born" from the host's mind after a few years. This happens to Harry Dresden himself in Skin Game, after Lash (a psychic copy of the Fallen Angel Lasciel who tried to possess him) sacrificed herself for him in White Night.
- The Goddess Athena conceives her children through the union of her mind with a mortal's. The exact mechanics of this are something nobody much wants to consider.
- In Star Trek: The Next Generation Deanna Troi gives birth a mysterious child.
- In Star Trek: Voyager, the Droid "One" existed due to a combination of Seven's nanobots and the Doctor's mobile emitter and self-terminated to keep the Borg from assimilating him. Both the Doctor and Seven were more or less parenting him during his almost Overnight Age-Up.
- Star Trek: Enterprise A hybrid clone child was produced using apparently stolen DNA (unspecified what kind) from Starfleet Commanders Trip Tucker and T'Pol. Neither parent was even aware of the child's conception, but once they found out they accepted her quickly enough.
- In Game of Thrones, Daenerys may have been invoking this trope when she decided to hatch her dragons on Drogo's pyre while she was also inside it. Mirri Maz Duur can be considered to be a "third parent" in the process.
- In Doctor Who episode "Journey's End", the hand the Doctor lost soon after regeneration produces a clone after it is touched by Donna Noble. This creates a clone of the Doctor that is half-human.
- The Inexplicable Adventures of Bob! — Molly the Monster was born when Dr. Jean Poule was running down the sidewalk carrying her grand experiment in a test tube, while Bob ran the other way carrying a jar of crunchy peanut butter. They collided, and the combined substances came to life. A month later, she was over five feet tall and talking. She calls Jean and Bob "Mommy and Daddy." This is, of course, all an homage to the old "You got your chocolate in my peanut butter!" ad campaign for Reese's Peanut Butter Cups.
- In Justice League Unlimited, Wonder Woman is apparently the phlebotinium child of her mother Hippolyta (as per her pre-New 52 comics origin) and her former lover Hades. According to Hades, he and Hippolyta sculpted Diana together. Hades taunts her by musing on whether Hippolyta brought Diana to life to have someone to remember him by when he was banished. It's never confirmed whether this was true or not, and Diana immediately decides it doesn't matter — Hippolyta is the only parent she has ever known and that's enough for her.