Three-Month-Old Newborn

A subtrope of Dawson Casting, one specifically about newborns, or at least TV "newborns". Whenever a supposedly just-born child appears on TV, the baby you will see will actually be several months old. Put this down to a mixture of simple ethics, employment laws, and casting laws that make it unacceptable to cast a real newborn in such a role. This is because sound stages are hot, bright, stuffy, dirty places—not a great environment for a newborn infant prone to infection and unable to control body temperature. And Now You Know.

This can have an unfortunate side effect, due to the fact that Reality Is Unrealistic, making a person's first encounter with a real newborn possibly squicky. Real newborns aren't clean-looking, gurgling bundles of cuteness. Real newborns are covered in things like blood, amniotic fluid, and other bodily substances, up to and including fecal matter. There is a chance they could be covered in a peach fuzz like substance called "lanugo" (a remnant of when our ancestors were a lot hairier than we are now; most fetuses lose it before birth but obviously, a few don't). Their skin will usually have a red hue to it as well, and look somewhat "wrinkly", especially if they are considerably premature. On top of all this most newborns have noticeably deformed heads from the birth process since their skulls aren't yet closed and their bones are very flexible. To say nothing of the placenta that should be popping out with the babe. Even newborns that have been cleaned up and are a couple days old are generally Ugly Cute at best. It's been said that all babies look like Winston Churchill.

This can even carry over to newborn animal babies, who fiction likes to depict as the cutest, smallest things ever to arrive, when in actuality most newborn animals arrive slimy, hairless, and often eyeless because their eyes may be covered by a layer of skin that takes some time to wither away. Take a look at a newborn rabbit, and you'll think your bunny just gave birth to a dumpling.

In fiction, birth is a much cleaner, nicer (but still painful for the mother) process, and in American films and TV shows usually happens in a tent. The four-month-old tot pops out of his/her Mommy as clean as whistle and is bundled up.

This is an Omnipresent Trope so only aversions, subversions, inversions, parodies and the like should be added.

Examples of Three-Month-Old Newborn include:

Film

Aversion: Children of Men used a CGI baby in the birth scene.
- Ditto for Revenge of the Sith, where both Luke and Leia are CG and so is the droid midwife.
Attempted aversion/bizarre example: Judd Apatow wanted to shoot an actual birth for Knocked Up; Anne Hathaway is said to have turned down the project because of this. Apatow abandoned this plan when he realized that he would need a worker's permit for the unborn child.
Taken to its most insane in Rudy Ray Moore's Petey Wheatstraw, the Devils' Son-in-Law, where the titular character emerges from the womb looking about twelve years old and wearing a diaper! He then attacks his doctor.
The Nativity Story is odd in the fact that while the baby playing Jesus could maybe pass for newborn, the baby John the Baptist comes out of the womb looking as if it's already attending preschool. The contrast between them makes the problem much worse than if they had used two older babies.
Total Aversion in the film Window Water Baby Moving by Stan Brakhage, in which Brakhage actually films his own wife in the few days before giving birth, as well as the filming during the birthing process... from up close. The fact that the film that there is no music or dialogue only highlights the intense (and squicky nature) of birth. The camera only being a foot away from his wife's... "area" also lends to this feeling.
Spike Lee's She Hate Me averted this in a rather traumatizing fashion. Not one, but two births were actually filmed and used in the movie. Pretty squicky stuff, especially since you expect the standard "mother screaming/cut to clean, swaddled child." Nope. You get two real kids popping out of real mothers right before your very eyes.
Likewise, the crew of Caligula kept a number of expectant mothers on set in order to capture a real birth for Caligula's child. When one of the women went into labor, she was immediately rushed onto the set and filmed.
In the TV movie Million Dollar Babies, about the Dionne quintuplets, the producers used animatronic dolls for the newborn quints. Using older babies to represent the newborn Dionne girls, who were two months premature, and small for that, would have been ridiculous, and defeatist as well, since it's a major portion of the first half-hour of the film that the girls are tiny, premature, and not expected to live. In addition to that, finding five babies who looked alike would be difficult. Obviously, using real, underweight newborns or preemies was out of the question. The film was made before CGI was an option.
Junior has Arnold Schwarzenegger give birth and like George Lopez they CGI his adult face onto a CGI baby... It's Nightmare Fuel for everyone, including Arnold, which is fair, as it is a nightmare in the film.
The French film Romance has what appears to be an actual birth. Close-up of vagina and everything.

Live-Action TV

Aaron on Lost was actually a newborn at birth, but thereafter was played by a series of significantly older babies. Of course, it's difficult to find blond, blue-eyed babies in Hawaii, especially to play a character who only ages two months in three seasons of episodes.
Inversion: In a Heroes flashback in season one, an eighteen-month-old Claire (an age when children are often walking and might even have a word or two in their vocabularies) was played by an eight-month-old baby.
- Could be justified, if Noah Bennett lied about her age to obscure the fact that Claire was obtained by theft, not private adoption.
Both used and averted on Desperate Housewives in season four: Danielle's son was born with amniotic fluid and all and looked like the average newborn for quite a while afterward, but Susan's (month early) son was born perfectly clean and looked to be the average size of a four month old baby.
Parodied on George Lopez. Anytime a flashback occurs where George is an infant, it's an infant's body with George's head computer generated on.
Similarly parodied in the Chappelle's Show parody of Antwone Fisher, where close-up shots of newborn Dave show his adult head. (Wider shots show an obviously fake baby - with an enormous penis.)
Hera on Battlestar Galactica is born tiny, bloody, and generally looking slightly premature.
Averted on Star Trek: The Next Generation episode "Disaster" when Keiko O'Brien gives birth to Molly with a cut-away shot that looks realistic.
According to the companion book, a half-Bajoran, half-Cardassian newborn was needed for an episode of Star Trek: Deep Space Nine, so they got the guys who built Chucky to do it. Sadly (and hilariously), the baby really looked like a Cardassian/Bajoran Chucky, so in the end they used a normal doll wrapped in a blanket and had one cutaway scene, using a four-month-old with a small rubber prosthetic forehead applied with K-Y Jelly.
Either TV Land or Nick-at-Nite once ran a commercial that lampshaded the entire TV-birth process, including this trope. It went something like this:

Kid: Where do babies come from?
Mother: Well, when two TV characters love each other very much, generally in the third season, the woman wears a very special pillow on her tummy. For three to five episodes. The man panics, and the woman is rushed off to hair and makeup, so she can look fresh as a daisy. And voila -- four-month-old newborns!

Not shown on camera, but a Law and Order about infanticidal teen parents averted the sanitized-birth elements of this trope, citing as evidence the gory mess (blood, amniotic fluid, infant feces) which the birth made of a hotel room.
Averted in the X-Files episode "Existence", in which the baby that plays William was Jerry Shiban, the son of John Shiban, one of the producers of the show. He was about two weeks old when he appeared in that episode, though when William returned for the next season, a different baby was cast due to Jerry's difficult temperament. Also the reason why William goes from being a redhead in season 8 to a blonde in season 9.
One Saturday Night Live skit has the newborn baby played by Will Ferrell.
The first-season episode "Brief Candle" of Stargate SG-1 appears to play this straight, with a newborn obviously larger than this troper's two-month-old child. May be justified, however, due to the Rapid Aging central to the plot.
In the fifth season premiere of Stargate Atlantis, the baby used to portray Teyla's newborn is about two weeks old. The commentary notes that they were counting down when the actual expectant mother would have her baby since it had to be at least 14 days old before they could use it in the scene.
Little baby Jake in the Sesame Street spin off, Sesame English (which teaches English to foreigners, starting with Taiwanese and Chinese), is portrayed by Roger Bart (who was 37 at the time of first airing) of all people.
Quite neatly averted in the Doctor Who episode "A Good Man Goes To War". Although it's the first time we see the baby, the previous episode ended just before the birth, and the opening scene appears at first to be just-post-birth, a throwaway line of dialogue near the beginning of the episode establishes that it's been a month since the baby was actually born, accounting for this trope.

Literature

Averted in the Tom Clancy novel The Bear and the Dragon, where President Ryan allowed the press to briefly film his newborn fourth child shortly after his birth.
Inverted in the Vorkosigan Saga, Bothari tries to pass the newborn Ivan Vorpatril as being a few months old, but the person he's trying to fool quickly figures out that the boy's stated age would be correct if he changed 'weeks' to 'hours'.

Periodicals

The Onion satirized this with one of its headlines: "Woman on TV gives birth to four month old baby".

Recorded and Stand Up Comedy

On one of his comedy albums, Bill Cosby describes how unprepared he was for his newborn's appearance:

"...As they started to clean it off... I went over to my wife, kissed her gently on the lips, and said, 'Darling, I love you very much. You just gave birth to a lizard.'"

- Ironically, when he got his own sitcom in the Eighties, he played an obstetrician.
- Robin Williams, in his concert at the Metropolitan Opera House, refers to his newborn son as "a little old man, dipped in 40-weight" (presumably, 40-weight motor oil).

Other Media

Quite common in paintings depicting Jesus's birth. This is an obvious case of All Painters Are Male, though, and at the times most of these works were made even married men didn't spend very much time around small babies. Also, a lot of times the patrons would pay the artist specifically to make the baby Jesus resemble a family member, if not the patron himself.