Now I Know What to Name Him

The parents' decision to name a child is made for them because they are informed of their offspring's future self, and the name of that future self, due to some sort of insight into the future.

For instance, when a woman's baby's daddy time-travels from the future back to the 1980s to protect her from a killbot. Or when a father knows what to name his daughter because she comes back in time to say, "Hi, I'm your future daughter named Lulu." Or a psychic tells mom and dad about their future son, Abobo. Or the virgin Mary being told by an angel about her upcoming pregnancy with baby Jesus, making this one Older Than Feudalism.

Usually a form of Stable Time Loop, unless time travel is not involved, such as when a woman has a psychic link with her unborn child.

Not the same thing as NameDar.

Comic Books

 * From Neil Gaiman's The Sandman, Lyta Hall is told by Morpheus that her son is named Daniel.
 * Justified in Elf Quest because elf mothers communicate telepathically with their foetuses.

Film

 * Sarah and John from Terminator, trope namer from the first movie where Kyle tells Sarah about John, to which she replies, "At least now I know what to name him."
 * A Nightmare on Elm Street 5: The Dream Child
 * Back to The Future: "Marty, what a nice name!"
 * An odd case, as they have children called David and Linda in the alternate future first.
 * Doesn't have to be that odd. For all we know David was an important name for one of their families. So it would make more sense to name their first born after that than some kid they knew for less than a week 10 years or so earlier.
 * Back to the Future doesn't work with a stable time-loop. Arguably, they were already supposed to name their third child Marty. He, perhaps, gave them the initial idea in this timeline, causing it to remain his name but he didn't inspire his parent in the original timeline.
 * We find out in Part 3 that Martin is a family name anyway.
 * The Time Traveler's Wife: they decide to name the daughter after he's met the future version of the daughter, who tells him her name.

Literature

 * The Bible, Luke 1, has two examples: An angel orders Zechariah to name his next son John. When he disbelieves that his wife was even pregnant, the angel gives him a bad case of laryngitis until Zechariah eventually writes on a writing tablet that the child's name will be John. Another angel tells a virgin named Mary that she is about to give birth to a son and name him Emmanuel.
 * Those aren't the only ones. There are a few others, not the least of which were the children of Hosea, with such meaningless names as (translated from Hebrew) 'not my people' and 'not your God,' just before God was to send the Hebrews into exile following a foreign conquest.

Live Action TV

 * The Sarah Connor Chronicles, episode Allison from Palmdale - Cameron's visage is based on a girl from the future named Allison. Cameron goes back in time and suffers a bit of Identity Amnesia, making her believe that she actually is Allison. Cameron calls Allison's mom and asks for help, but Allison's mom says that she doesn't have a daughter. At least not yet, because she is pregnant, and Allison's mom says that Allison is a "very pretty name."
 * On Charmed, Piper and Leo's second son is named Chris, and the only reason they know is because he came back in time.
 * In the Doctor Who episode "Let's Kill Hitler" we discover that Amy named after . Who turns out to be ....
 * In the Norwegian children's TV series Broderne Dal og spektralsteinerne, three time-travelling brothers end up having an adventure as adults with their father as a youth, when he is a member of La Résistance in Norway during the German Occupation of WWII. In the end, he asks the names of the people who helped him, and assures them that if he ever gets three sons, he will name them after them. (He has no idea who they are, of course).

Webcomics

 * In the future arc of Arthur, King of Time and Space, Morgana ended up naming her and Arthur's child, who was sent back in time, after an impressive ensign aboard the Excalibur. They end up conversing and she realizes she named her son, Mordred, after his future self.
 * General Protection Fault, Ki meets her son from the future.

Western Animation

 * In one episode of Peter Pan and The Pirates, Peter brings another girl to Neverland, a pigtailed creature called Jane. The cast eventually works out that Peter accidentally went into the future and collected Wendy's daughter. She goes back at the end of the episode.

Video Games

 * In Sin and Punishment, Achi shows Airan a Story-Boarding the Apocalypse sequence to convince her to subdue Saki. In this sequence, she is accompanied by a young child named Isa ("I can even write it in kanji!"), who turns out to be Saki and Airan's son. Airan takes this revelation to heart, as one of her main priorities in the ending is to make sure that Isa is born at the right time. And, wouldn't you know it, Isa is one of the main characters in the sequel.
 * In Jak and Daxter a young boy is found wandering the city. He is referred to only as "the kid" and none of the characters learn his actual name. Later it is revealed the kid is actually . Although not a biological parent, it can be assumed that Samos started calling him that after.