A Hero Is Born

What better way to introduce the protagonist of the story than start at his/her birth? This device is used often and is used to have the audience fall in love with the character, because who can't love a baby?

Mainly comes in two types.
 * Type 1: Work literally begins from the birth of the protagonist. A Time Skip or two are permitted.
 * Type 2: Protagonist is shown as an infant at the beginning. Might overlap with Door Step Baby.

Compare A Minor Kidroduction.

Anime and Manga

 * The manga adaptation of The Legend of Zelda: Oracle of Seasons opens with Link's birth, showing his Triforce mark from those games as a birthmark.
 * Rose of Versailles begins just a moment before the birth of Oscar.

Film

 * Look Who's Talking starts at conception. Actually a few moments before conception.
 * James Kirk in the latest Star Trek movie. A deleted scene would also have done this with Spock.
 * Gattaca
 * Amelie actually begins with the conception of the heroine.
 * Twins

Literature

 * Stories of King Arthur tend to begin with the retelling of his conception, a rather convoluted event involving adultery, war and magic, following in the tradition of Celtic heroes having unusual affairs. By the time of Malory it's even more nuanced as he has to keep the story of the strange conception, but also needs to make sure that Arthur isn't a bastard. Hard to make that work. The story then goes on to his birth and how Merlin christens him and whisks him away to Sir Ector.
 * Tennyson has a very different account of Arthur's arrival, having him wash up on shore in a manner similar to Schyld Schefing, on the night Uther dies. All part of setting him up to be a truly pure hero.
 * And, speaking of which, Schyld Schefing of Beowulf. The book begins by recounting his birth and life, even though the story isn't about him.
 * Averted with Beowulf, oddly enough for an epic, who enters the story from a foreign land, long grown up, and little about his childhood is ever revealed, save that he was weak as a child. This seems a small subversion of the typical hero story when they are born under unusual circumstances and have remarkable childhoods, but the unassuming child has become a recognizable trope in itself.
 * White Fang (it starts a little before the birth of White Fang, actually).
 * Tristram Shandy by Laurence Sterne, which begins with the hero's conception. And his troubled birth sets up much of the humor that follows.
 * It's kind of a parody of this trope, considering the rest of the book(s).
 * In RA Salvatore's Drizzt Do'Urden series, one of the prequel books starts off with Drizzt's birth, and the consternation surrounding it.
 * Both Moses and Jesus in The Bible.
 * Tarzan The original story "Tarzan of the Apes" starts with the adventures of his parents and is already well into its third chapter before Alice Clayton saves her husband's life, kills a bull ape, becomes insane and bears Tarzan in less than a day.
 * The Gormenghast novels were conceptualized as the fictional biography of the protagonist from birth to death. The first book begins on the day of his birth and follows the events surrounding his infancy. Instead of going on with a Time Skip, the first book ends before our protagonist is even old enough to speak.

Theatre
"His hair is fuzzy, his eyes are blue, His eyes may change--they often do. He weighs eight pounds and an ounce or two-- Joseph Taylor, Junior!"
 * Rodgers and Hammerstein's Allegro:

Video Games

 * The protagonist of Fallout 3
 * The first memory in Assassin's Creed II is of Ezio's birth.
 * Dragon Quest V.
 * The Famicom RPG Tao provides opening exposition while an embryo - presumably the protagonist's - gestates in the background.
 * Traverse: Starlight & Prairie.

Western Animation

 * Bambi in Bambi
 * Littlefoot in The Land Before Time
 * Simba in the The Lion King.
 * One Hundred and One Dalmatians - 13 of the main characters were shown being born.
 * Finding Nemo - Nemo was shown as an egg.
 * Hercules - Hercules was not only once a baby, he was once a god.
 * After the opening Oner, Spirit: Stallion of the Cimarron begins with Spirit's mother in labour.

Anime and Manga

 * Naruto began with the details of what happened to him as an infant.

Film

 * The Outside Chance of Maximillian Glick opens up at the title character's bris.
 * Years before the version of The Wizard of Oz everyone remembers, there was a silent adaptation of The Wizard of Oz that, among many, MANY other changes, established Dorothy Gale's arrival in Kansas as a Door Step Baby delivered by a mysterious, supernatural figure.

Literature

 * Harry Potter, in full Door Step Baby mode.

Video Games

 * Mario and Luigi for the entire game of Yoshi's Island.

Web Comics

 * Drowtales: here.

Western Animation

 * The Hunchback of Notre Dame - Yes, Quasimodo was a baby.
 * Aladar the Iguanodon in Dinosaur is taken from his mother's nest as an egg by a Pteranodon and winds up hatching in the presence of a family of lemurs.

Please sort if you know which type the examples are

 * The Curious Case of Benjamin Button
 * IIRC, this one has elements of both types because in the movie, it shows Benjamin's birth and then him being delivered as a doorstop baby to Queenie. In the original story, it only has his birth as he is raised by his actual parents. It's kind of a weird inversion anyway since in his "infancy" he's an adult.