Gender

Gender or sex is a categorical or social construct, pertaining to male or female. Pokémon, not unlike humans, have sexual differences (dimorphism).

Gender differences
Generation IV premiered minimal differences in sprite between two Pokémon of the same species. For example, a male will have the full tail seen in previous games, while the female is missing the very tip of it. Generations V and would introduce Pokémon with more drastic differences in appearance.

The only Pokémon with gender differences that are not just aesthetic is, which has different learnsets and depending on its gender. The male Meowstic has and the female Meowstic has  as its Hidden Ability. Furthermore the male Meowstic learns mostly status moves, with all of its gender-exclusive moves being status moves, while at the same levels, the female Meowstic learns mostly special moves, with only one of its gender-exclusive moves,, being a status move. Below are Meowstic's learnsets.

Related species
The Nidoran family is a special case in terms of gender. Introduced in Generation I, before gender was known for all Pokémon, and  are considered separate species of Pokémon and indeed have many differences, from appearance to moveset. However, Nidoran Eggs have a 50/50 chance of hatching into either Nidoran♀ or Nidoran♂.

In a manner similar to, Eggs produced by may hatch into. While and  are in the  in the games, likely due to being Legendary Pokémon, Latias have produced Eggs containing  in the anime, confirming that they are similarly related.

Gender-based evolutions
Some Pokémon may have different ways of evolving depending on their gender. These Pokémon may therefore have one or more evolutions that can only be a single gender.

Other single-gender Pokémon
The following is a list of all Pokémon that are either 100% male or 100% female and have not been mentioned in an above section. In particular, these Pokémon have no explicit relation to a Pokémon of the opposite gender through evolution or breeding, although some of them may have a counterpart such as with and.

In battle
The is more effective when catching Pokémon that are of the same/opposite gender of the player's Pokémon.

The following moves are dependent on gender:

The following Abilities are dependent on gender:

Characters
See:.