There has been a great many arguments that are probably best left off the wiki about when a person actually becomes a person. Is it when they're born? Is it when they're still in utero but starting to look like a baby? Or is it even when they're still a zygote? Most people agree that a sperm by itself (and an ovum by itself) is not a person. In fiction, on the other hand...
This trope is, essentially, when sperm cells are anthropomorphized. Quite often, the sperm will have attributes like facial features or personality similar to either the man they're "living" in or the man's child they will end up conceiving. They will treat conception like a big event, often a race, with the egg as the "prize".
On the subject of the egg, it is rarely anthropomorphized in the same way, possibly because ova do not move in the same way sperm do, but on the rare cases it is anthropomorphized, it will be a female, just as the sperm are nearly always portrayed as male (although the sperm might be portrayed as female if carries the XX chromosomes to conceive a girl).
Another weird point is that the semen they're supposed to live in is often not visible, possibly so that the living sperm can be seen clearly, not to mention the fact that physical depictions of semen are more often than not considered Not Safe for Work.
Conception is usually portrayed as the sperm forcing its way into the egg or just sitting next to the egg, and what happens to the other sperm cells is either they get disappointed, they just disappear, they die, or it's not touched upon. It's actually much more complex in Real Life, with the egg outright walling itself off from further sperm cells after fertilization, while the cells that didn't make it end up dying; even getting to the egg is a bigger hassle than popularly portrayed, as many cells die along the way due to the high acidity of a woman's... inner sanctum. Of course, don't expect any of this to be touched upon in most instances of this trope, as real-life complexities don't exactly make for a cohesive one-off segment in a narrative.
A variation is when a person tells another person about "when you were a sperm" or mentions "when I was a sperm" or talks about "having been the fastest sperm".
Sub-trope of Anthropomorphized Anatomy
This trope is often used to either teach kids about "the birds and the bees" or as Vulgar Humour. Compare Anthropomorphic Food, Living Toys, Animate Inanimate Object, Egg Folk and Talking Poo for other anthropomorphic things, and I Call Him "Mr. Happy" for more realistic personification that has to do with male privates. Not Truth in Television of course, but for centuries, it was thought to be. Sperm cells were thought to contain "homunculi", i.e. tiny humans who developed in the woman's body.
- A banned commercial for Durex condoms has a man meeting with a woman for a date, only to be trampled over by a bunch of anthropomorphic sperm that come racing straight towards the woman, only to be stopped by a wall of latex (presumably the condom being advertised).
- An episode of Panty & Stocking with Garterbelt has a parody of the D Day landings with sperm as the soldiers of a man jacking off with Kleenex, which kills the sperm on contact. Their ghosts act as the Monster of the Week, who destroy stocks of tissue as revenge. The ending revisits the regular sperm, where their attempts to fertilize are again thwarted, this time by a condom.
- Cells at Work! CODE BLACK, being a series in which all bodily cells are anthropomorphized, obviously utilize this trope upon discussing the nature of sperm cells. Here, they're depicted as people wearing sperm-shaped mechanisms around their torsos, complete with flagella.
- Several baby onesies have writing about being sperm, with messages ranging from "Daddy's little squirt" to "I won my first race" to "I was nearly swallowed".
- One The Far Side comic has some sperm pretending to have different occupations so that the egg will "let them in". Another has a sperm with an outboard motor.
- A B. Kliban cartoon titled "My Dad, the Swimming Champ", depicts a giant sperm in a necktie leaning against a fireplace mantel that holds a gigantic trophy.
- Bride of Frankenstein has homunculi (tiny people thought to come from sperm in the past) living in a jar.
- Everything You Always Wanted To Know About Sex But Were Afraid To Ask: The final sequence has this, with the egg being non-sentient, and a goal for the sperm. It also has a brain trying to figure out how to make the man have an erection, and sperm talking to each other about condoms and homosexual encounters]
- The opening/fertilization sequence of Look Who's Talking.
- Played with in The Mating Habits of the Earthbound Human, where humans in white outfits are used as symbolism for sperm. They then reach the end of the track and are confused at not finding an egg, get caught in a plastic tarp, and get gunned down to symbolize non-vaginal sex, condoms, and spermicide respectively.
- Implied in Osmosis Jones: One scene inside Frank's brain has a likeness of a sperm cell on a pedestal, which is drawn completely realistic unlike the other cells, but is credited as "Our Founder".
- One joke involves a conversation between sperm.
Sperm 1: I am the strongest, I will get to the egg first.
Sperm 2: I am the fastest, I will get to the egg first.
Slow Sperm Who Hadn't Spoken: Guys, are you aware we are all actually inside a condom? (everyone leaves except him) And this is how geniuses are born!
- Comparable setting, the Orphaned Punchline suffices: "Run for your life, it's a blowjob!"
- Its Not The Stork anthropomorphizes the sperm, the egg, and the zygote.
- Inverted in Middlesex, in which Cal imagines himself and his brother as tiny homunculi inside their eggs, waiting to be fertilized.
- In Mummy Laid An Egg, the kids draw faces and speech bubbles on the sperm, which they call "seeds".
- Where Willy Went is about a sperm named Willy and his rival Butch. The strange thing is, Edna Browne, the girl Willy conceives, is bad at math and good at swimming, like Willy was.
- Episode "Backward" of Red Dwarf is set in a dimension where time and aging works backwards. Lister dreads becoming a sperm.
Lister: And worse than that — in 25 years I'll be a little sperm, swimming around in somebody's testicles! I mean, pardon me, but that's just not how I saw my future!
- In Star Trek: Voyager, the episode "Someone to Watch Over Me", has the Doctor try to teach Seven of Nine how to date. Seven, due to being raised by a hive mind of emotionless cyborgs known as the Borg, doesn't see the point of romance and thinks it's all about procreation. When the Doctor goes through the mating habits of various alien species, he starts explaining how procreation works, describing the ovum as a "fortress" and the sperm as "little warriors". Seven of Nine interrupts, saying that she already knows how that works.
- The Koit song "Egg and Sperm" is about some sperm trying to reach the egg.
- NSFW Comix in the early days has two "left-dwellng" sperm characters and their shenanigans to fertilize an egg. One is portrayed as a Soviet, the other a beatnik.
- This Bored Panda list of funny things said by kids and one was a boy who said that he wasn't in an old picture because he was still swimming in his daddy's balls.
- In the Weebl & Bob music video "Babies", sperms with Weebl's face are briefly seen swimming towards an egg cell.
- Beavis And Butthead: In "Beavis and Butthead Do America", Beavis has a flashback of himself as a nose-picking sperm.
- Family Guy portrays sperm as Space Fighters, piloted by homonculi that look like the children they would conceive, who fight to reach the ovum. Stewie mentions he reached it because of the determination he developed at "testicular boot camp".
- The Simpsons:
- In "Brother, Can You Spare Two Dimes?", Homer and Smithers' sperm samples are seen with their owner's faces. Smithers' healthy sperm swim in organized swarms. Homer's swim randomly and knock into each other, demonstrating that the nuclear plant has rendered him infertile.
- In "And Maggie Makes Three", Maggie's conception is depicted with a bunch of clumsy, Homer-headed sperm cells. As this was part of a Whole Episode Flashback recounted from Homer to his children, it leads to a cut to Homer pantomiming a wriggling sperm as the others chew him out for the pointless gross detail.