Pokemon come in all shapes and sizes; some are big, hulking beasts, while others are timid fragile creatures. As well as appearances, they're separated by types - water, fire, grass, and so on. There is one other attribute that sets Pokemon apart - their gender.
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Most Pokemon are either male or female, and while this is largely unimportant for gameplay, it can be relevant if you're trying to breed them, and some species have differences between the male and female members. There are a few Pokemon, however, with no known gender at all. This includes Legendaries (likely genderless to keep them rare and prevent you from breeding hundreds of them), but also a handful of regular Pokemon. Here are some of the best such critters, who, for various reasons, have no known gender recorded in the Pokedex.
10 Minior - The Living Meteor from Outer Space
Minior live in the upper atmosphere, feeding on space dust. When they've consumed enough, their shells grow sufficiently heavy to fall to the Earth, where they're caught by trainers. Found initially in the Alola region, they have two forms - one with their rocky shell still intact, and one having shed it, exposing their bright core.
Why exactly Minior have no gender isn't entirely clear. Rocks in the real world have no gender, but this is Pokemon, where Geodude are just gendered, muscly pebbles. Minior's core is seemingly pure cosmic energy, so that's likely a factor - perhaps its otherworldy composition is simply beyond human understanding.
9 Dhelmise - The Spooky Spirit of the Sea
Composed of an anchor and a ship's wheel, and held together by some possessed seaweed (which is the true body of Dhelmise, at least in the biological sense), this nautical ghoul is another Alolan native. It lurks the waters around Alola's islands, using its anchor as a weapon to take out larger prey such as Wailord.
Assigning a gender to a possessed piece of nautical equipment seems like a tricky task, so it's fairly obvious why Dhelmise's Dex entry is another "gender unknown". Interesting to note, though, is that seaweed in real life does actually have male and female variants - and reproduces accordingly.
8 Cryogonal - The Beautiful Snowflakes who Hate Summer
Off to Unova now, where the snowflake Pokemon Cryogonal were first discovered. Formed just like real snowflakes in freezing clouds, these Pokemon fall to the ground, where they roam around until it gets too hot and they evaporate again. According to their Dex entry, Cryogonal use chains made of ice crystals to capture prey.
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Given that they're made up almost entirely of water, it's fairly clear why Cryogonal lacks conventional gendering. It certainly doesn't detract from their coolness though (no pun intended), as these frosty hunters are a favorite of many playing through Pokemon's answer to New York.
7 The Magnemite Line - The Original "Object Pokemon"
These days, everyone has an opinion on "object 'mons" like Vanillish or Palossand - you either love themor hate them - but back in the 90s, Magnemite was doing it before it was cool. A couple of magnets attached to a metal ball (and its evolution - three such balls stuck together), these metal orbs are surprisingly endearing.
If you've ever held a magnet, you've probably noticed its lack of any noticeable masculinity or femininity, so it makes sense for that to carry over to Magnemite. They might have no known gender, but in generation 2, they did get the new and exciting steel type - the only Kanto Pokemon to do so.
6 Shedinja - The Untouchable Ghost in a Cicada Shell
If you've ever ventured into Pokemon Showdown, you've likely encountered a Shedinja. While they only have a mere 1 HP point, these Pokemon are, in a way, defensive walls due to their Wonder Guard ability - only super-effective moves do damage, so they're immune to over half the types in the game.
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When Nincada evolves into Ninjask and casts off its shell like a real-world cicada, Shedinja is formed when a ghost inhabits that shell. It's therefore quite clear why we can't gender them for breeding purposes - any actual biology would stay on Ninjask, so there's nothing on the shell.
5 Rotom - The Phantom with a Taste for Household Appliances
Introduced in Sinnoh, where one lurked the Old Chateau, Rotom is a hyperactive ghost that, as opposed to ship parts or bug sheddings, has a particular liking for everyday household appliances. Being primarily electric-ghost, its form changes (and its typing, as of generation five) depending on what it possesses, making it very versatile.
It's clear by this point on the list that the scientists of the Pokemon world are yet to understand the genders of ghosts, and Rotom is no exception. Its forms don't offer much help either - lawnmowers, washing machines, and refrigerators are about as inanimate as it gets.
4 Staryu and Starmie - Just a Pair of Starfish (Albeit Psychic Ones)
Made infamous by Misty all the way back in generation one, Starmie has probably burned into the minds of countless 90s kids thanks to the trauma of facing the bubbly gym leader and her starfish ace.
Unlike many Pokemon on this list, who lack a conventional gender due to being beyond human understanding, or being inanimate objects, the Staryu line is different. While some real-life starfish have males and females, others are hermaphrodites, meaning they can change their biology to be either male or female. Based on the Pokedex, it seems the same is true of the Staryu line.
3 Porygon - A Man-Made Wonder of Technology
Manufactured by Cinnabar Island's Pokemon Lab and distributed by the Silph Co. in Saffron City, Porygon (and its subsequent upgrade Porygon2 and corruption Porygon-Z) is an obviously unique Pokemon.
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Resembling a sort of low-poly pink and blue duck, this Pokemon doesn't have a gender presumably because it wasn't given one by its creators. They likely deemed it unimportant, or preferred just to focus on aspects of design they deemed more vital, like battle prowess. Porygon is a beloved and iconic Pokemon, however, so it's clear its lack of gender as we know it hasn't held it back.
2 Falinks - A Squadron of Tiny but Brave Warriors
The youngest Pokemon on this list, Falinks were introduced in generation eight's Galar region. Looking like a caterpillar at first glance, they're actually a group of six individual creatures, marching in a well-disciplined single file. These Pokemon's battle-ready attitude, in contrast with their small stature and cute appearance, makes them very endearing and they quickly became a fan-favorite.
Falinks' reason for lacking a Dex gender is obvious - "a" Falinks is composed of several creatures. Some might be male, some female, some something else entirely. There's likely to be some variance within the group at least, so it's impossible to gender them as a whole.
1 Ditto - An Adorable Blob with an Interesting Biology
Another Kanto Pokemon, Ditto is actually quite tied into the lore found in the generation one games. The closest thing Red and Blue (and their many sequels and remakes) have to a story is the mystery of the Mythical Mew, and its Legendary clone Mewtwo. It's hinted that Ditto are actually failed Mew clones, essentially being almost raw DNA.
They're not biologically developed enough to have a gender as we know it, but they do have some interesting capabilities - because of their form being so basic, not only can they transform into any other Pokemon, they can also breed with any other Pokemon (aside from Legendaries), including all those on this list. Ditto is a beloved Pokemon, and rightfully so - it's an icon, a genius concept, and a fantastic example of a Pokemon that doesn't need fancy gender differences to be great.
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