In the real world, maternal impression is a discredited medical theory that held that emotional stimulus experienced by a pregnant woman could influence the development of her baby. This theory is known to go back at least as far as Ancient Greece, making it Older Than Feudalism, and was popular until the rise of modern genetic theory.
Historically, it was typically an explanation for the existence of birth defects and congenital disorders (and as an excuse when a baby didn't look like the supposed father, such as in cases of a Chocolate Baby). Modern genetic theory has been a Trope Breaker for that, and it has mostly become a Forgotten Trope. When it crops up in modern works, it will typically be as a Downplayed Trope or Implied Trope, such as children taking on characterological traits via Rule of Symbolism.
This is not merely Shared Family Quirks, Like Father, Like Son, Strong Family Resemblance, or even Generation Xerox. These children are not just like their parent(s) in general — they are specifically influenced by their parents as they were in the context of the child's conception, or their mother as she was during her pregnancy. If non-genetic traits are inherited, but not specifically something related to the circumstances of conception or pregnancy, then it's instead Lamarck Was Right or Genetic Memory.
Modern medicine generally agrees that things such as illness and drug use during pregnancy can impact a baby in utero, and so One Drink Will Kill the Baby and Childhood Brain Damage should not be considered this. The difference is that those are physical stimulus, while Maternal Impression involves emotional or symbolic stimulus. Likewise, Functional Magic impacting a baby in utero is Mystical Pregnancy, not this.
Super-Trope to:
Examples:
- Aethiopica (a Greek romance from the 3rd century AD) starts with Queen Persinna of Ethiopia giving birth to a white daughter, despite her and her husband being black. She gives the baby away to avoid accusations of adultery. After many adventures, it is revealed that Persinna had been looking at a painting of Andromeda while she conceived, and so Andromeda's appearance (including white skin) "imprinted" on her child.
- Dollanganger Series: Downplayed or Implied, as expected in a modern work. In a quest for revenge against her mother, Cathy seduces her mother's husband and Baby Traps him. That's how her son Bart is conceived. It's not until ten years later—when Bart starts to exhibit some of Cathy's most vengeful traits—that she thinks maybe that was a bad idea.
Cathy: The child of my revenge.
- The Hampdenshire Wonder: The Child Prodigy Victor is the son of the former cricket player Ginger Stott, whose plan was for Victor to have no exposure to cricket until the age of fourteen so Ginger could train him properly, without any bad playing habits forming in his childhood. The unnamed narrator thinks that Victor's parents' desire for him to have no preconceptions caused him to be born without instincts at all — he had no heartbeat at birth, and had to be taught everything that other infants know instinctively. The narrator thinks it is this lack of instincts that allowed Victor's mind to become so advanced.
- At the end of Horton Hatches the Egg, the chick that emerges from the egg has elephant features because Horton, not the deadbeat mother, guarded it.
- Mademoiselle de Scuderi: Cardillac claims that his obsession with jewelry stems from an incident where a nobleman clad in gemstones seduced his pregnant mother and went Out with a Bang.
- Middlesex: After returning home from a sexualized production of the play The Minotaur, Desdemona and Lefty have sex, as do Lina and Zizmo. Desdemona — who is actually Happily Married, but also quite old-school and doesn't feel comfortable admitting the play turned her on — pretends to be asleep. Both pairs conceive a child that night. These circumstances of their conception are not particularly imprinted on either of the two babies. But this book is a Generational Saga, and years later, when those two babies grow up, marry each other, and have a child of their own, that kid sees reflections of himself in his parents' conception.
Cal: Parents are supposed to pass down physical traits to their children, but it's my belief that all sorts of other things get passed down, too: motifs, scenarios, even fates. Wouldn't I also sneak up on a girl pretending to be asleep? And wouldn't there also be a play involved, and somebody dying onstage?
- In 100% Wolf, lycanthropy is hereditary instead of being something passed by bite. However, the reason why Freddy winds up turning into a poodle instead of a wolf is apparently because his mother gotten bitten by one while pregnant with him.
- A Song of Ice and Fire: Westerosi culture holds that bastards are inherently deceitful and sexual because they are born from infidelity. The narrative of the series does not hold that this is true, though, and the bastard characters we meet have a range of personalities as much as anyone else.
Egg: Trueborn children are made in a marriage bed and blessed by the Father and the Mother, but bastards are born of lust and weakness, he said. King Aegon decreed that his bastards were not bastards, but he could not change their nature. The High Septon said all bastards are born to betrayal...
- Versailles: This is a Discussed Trope as a possible explanation for a Chocolate Baby, although it's such a painfully weak excuse that no characters give the idea any credence.
Doctor: As for the condition of the child, I have an explanation.
Louis: [sarcastically] I cannot wait to hear it.
Doctor: As you know, sire, Her Majesty has enjoyed the company of a little blackamoor, Nabo. She liked to play games with him — peekaboo and so on. As I understand it, sire, shortly after Her Majesty fell pregnant, Nabo hid behind a piece of furniture and jumped out upon her to give her a surprise. And he gave her a look of such force that it served to corrupt the royal womb with darkness.
Louis: [sarcastically] It must have been a very penetrating look.
- The Talmud
- Various explanations are given as to why the first-century sage, Elisha ben Avuya, became a heretic. Among these is that when his mother was pregnant with him, she used to pass by pagan temples and enjoy the scent of their incense.
- Another story tells of how Rabbi Akiva explained a Chocolate Baby to a dark-skinned king by theorizing that the queen must have been looking at white marble statues when she conceived, making the baby white.
- An Urban Legend holds that a plantation-master's wife in Antebellum America blamed her giving birth to an obviously black child on the fact that there was a painting of a black man in the study where she frequently spent time.
- Crusader Kings II: One event has the player character's wife request strange foods due to pregnancy cravings. The food you let her eat determines a birth defect in the child: quail's feet cause the child to be born clubfooted, a hare's head guarantees a harelip, and a fish's eye will make the child ugly.
- Looney Tunes:
- "Porky in Wackyland": A three-headed creature looks at the audience and says something in gibberish, which another creature translates as "His mother was scared by a pawnbroker's sign." A pawnbroker's sign traditionally consists of an image of three balls, the idea being that because his mother was frightened by an image of three balls he was therefore born with three heads.
- "Yankee Doodle Donkey": A donkey disguises himself as a dog to join a canine army troop. When his tall ears accidentally peek out from his helmet, the drill sergeant quips, "Was your mother ever frightened by a mule?"
