Holy Child

A young child of either gender who is sought after by both the bad guys and the good guys for more than one reason. They may be The Chosen One, or holding the key or the secret to something, That makes this kid one of a great importance to all around him or her...

See also MacGuffin Girl, Mystical Waif, Kid Hero, The Fool.

Anime and Manga

 * In Franken Fran, a girl is this to a sect. The building of the sect becomes her body. Then she gets pregnant. And when the embryo awakens, mother and child merge to become the Flying Spaghetti Monster.
 * Azumaria from Chrono Crusade.
 * Madoka Kaname from Puella Magi Madoka Magica has a huge potential to become a powerful Magical Girl. This drives a lot of the conflict, as Team Pet Kyubey wants her to take up the role, but Dark Magical Girl Homura wants to stop her from doing so,  Eventually we learn that in this setting Holy Child also means.
 * Hikari / Kari, from Digimon Adventure. Hunted by because she's . Heck, one of her image songs is even called "Holy Light."

Literature

 * Harry Potter in the first book.
 * In the Dune universe, Alia Atreides was considered this when she was a girl. After she grew up and became a tyrant, not so much. Also, Leto II and Ghanima as children.
 * Pomma D'ok and Teera Eld in Zilpha Keatley Snyder's Green-Sky Trilogy. After they, they are literally named Holy Children and worshiped by most of the people.

Film

 * Enola in Waterworld.
 * The Dalai Lama in Seven Years in Tibet.
 * Bless the Child
 * Little Buddha: A child is thought to be the reincarnation of Lama Dorje.
 * The Golden Child
 * Elora Danan in Willow.

Live Action TV

 * Stargate SG-1 used it a couple of times, first with the Harsesis and later with Adria.
 * The X-Files has Baby William, who is heralded as this. He is described as "more human than human", a normal human child with none of the human frailties. He is seen as the salvation of the human race from alien invasion; he is the epitome of what the Syndicate has been trying to do for years: create a human/alien hybrid. While they did it in a lab (with diastrous results), William was gestated naturally. If they can figure out to replicate that, or make a vaccine against the alien virus, the human race has a chance of surviving. So, they're after him. And the Super Soldiers, who are bent on making sure alien invasion is swift and that resistance is futile, are after him to kill him. On top of that, he is kidnapped mid-season 9 by a UFO cult who are convinced he is connected to a UFO they found. He has supernatural powers, most notably telekinesis. He is seen making the mobile above his crib move on its own (scaring his mother to death in the process).
 * He also has a Christ-like birth, with Scully giving birth in a shack in the middle of nowhere, a guiding star, and the Lone Gunmen acting as the Three Wise Men. Though it took place in mid-May, not December.
 * Angel: A few of these crop up during the series, notably in the series 2 episode "Judgement" and the series 5 episode "Time Bomb".

Video Games

 * Sheba is considered one in Golden Sun.
 * That kid in the Villagers game.
 * A somewhat older version is the teenaged Diadora from Fire Emblem Jugdral, since
 * The center of the conflict in Fahrenheit.
 * Mithra from Asura's Wrath can freely manipulate Mantra to a point where she can be used as apower source to increase the power of the deities.

Western Animation

 * Aang from Avatar: The Last Airbender.
 * King of the Hill episode "Won't You Pimai Neighbor?": Bobby is thought to possibly be the reincarnation of Lama Sanglug. The monks display several items on a blanket, and Bobby is to choose from any item that he sees. If Bobby is the Lama, he will choose an item that was the possession of the Lama. Bobby doesn't want to be a monk, so he chooses Connie, whom he sees in a mirror amongst the items. The monks accept this and leave...but the mirror was the item the Lama owned!
 * Subverted (in the respect of "child") in an episode of Jackie Chan Adventures where holy monks believe Tohru is their reincarnated Chosen One.

Real Life

 * As mentioned already, this is the whole deal behind the search for the Dalai Lama.