Gender
Gender is a concept introduced in Generation II, though touched upon in Generation I. In Gold and Silver Versions, all Pokémon of most species were assigned a gender (male or female), and then, in Pokémon Crystal, a choice of male or female player characters became available for the first time. This feature allowed for Pokémon breeding, as well as introducing the concept of a Pokémon egg to the series. Gender makes no difference in the stats of a Pokémon after Generation II, unless the two Pokémon are a different species entirely, such as Nidoran.
Pokémon
Related species
Nidoran
The Nidoran family is a special case in terms of gender. Introduced in Generation I, before gender was known for all Pokémon, Nidoran♀ and Nidoran♂ are considered separate species of Pokémon and indeed have many differences, from appearance to moveset. However, a Nidoran♀ egg always has a 50/50 chance of hatching into either a Nidoran♀ or a Nidoran♂, confirming that they are related.
| Male | Female |
|---|---|
 Nidoran♂ |
 Nidoran♀ |
 Nidorino |
 Nidorina |
 Nidoking |
 Nidoqueen |
Other
In a manner similar to Nidoran, eggs produced by Illumise may hatch into Volbeat. Mothim and Wormadam evolve from male- and female-gendered members of the same species.
| Male | Female |
|---|---|
 Volbeat |
 Illumise |
 Mothim |
 Wormadam |
Unofficial counterparts
Gender also allowed for many Pokémon to have unofficial male and female counterparts, as demonstrated below.
| Male | Female |
|---|---|
 Tauros |
 Miltank |
 Latios |
 Latias |
 Gallade |
 Gardevoir* |
 Glalie* |
 Froslass |
 Washibon |
 Baruchai |
 Wargle |
 Barujiina |
| *Can be either gender | |
Gender differences
Generation IV premiered minimal differences in sprite between two Pokémon of the same species. For example, a male Raichu will have the full tail seen in previous games, while the female is missing the very tip of it.
Gender-based evolution
Some Pokémon evolutions can only be obtained if they are of a certain gender:
- Female Combee evolve into Vespiquen at level 21. Male Combee never evolve.
- At level 20, female Burmy will evolve into Wormadam and male Burmy evolve into Mothim.
- Only male Kirlia can evolve into Gallade.
- Only female Snorunt can evolve into Froslass.
Single-gender Pokémon
Several Pokémon are also only of one gender, yet do not have an official or unofficial counterpart of the other.
| Pokémon | Gender | Pokémon | Gender | Pokémon | Gender | Pokémon | Gender |
|---|---|---|---|---|---|---|---|
 Happiny |
♀ |  Smoochum |
♀ |  Tyrogue |
♂ |  Dageki |
♂ |
 Chansey |
♀ |  Jynx |
♀ |  Hitmonlee |
♂ |  Torunerosu |
♂ |
 Blissey |
♀ |  Vespiquen |
♀ |  Hitmonchan |
♂ |  Borutorosu |
♂ |
 Churine |
♀ |  Kangaskhan |
♀ |  Hitmontop |
♂ |  Randorosu |
♂ |
 Doredia |
♀ |  Cresselia |
♀ |  Nageki |
♂ | ||
Trainers
Starting in Pokémon Crystal, players were given the option of choosing to play as a boy or girl Trainer at the start of the game. Since then, every game in the main series has included that choice.
In side games
Many side games in the Pokémon franchise also allow the player to choose between a male or female player character as well.
Trivia
- In Generation II, there was a feature called the Time Capsule allowing compatibility between this generation and Generation I. In Generation I, all Pokémon were genderless. But in Generation II, genders were introduced. And upon trading with the Time Capsule, the gender of the Pokémon would be redetermined, (if traded from Gen I to II), mostly through IVs.
- Due to the programming in the Generation II games, female Pokémon can never have a maximized Attack stat unless they are a female-only species such as Miltank; this is because female Pokémon cannot have Attack IVs greater than or equal to a value based on their gender ratio. Female-only species have a 100%, or sixteen-out-of-sixteen, chance to be female, so their Attack IV can be anywhere in the 0-15 range, which is sixteen values. Pokémon who have a 12.5% chance to be female, such as starter Pokémon, only have a two-out-of-sixteen chance to be female, which means that they can only have a zero or one Attack IV. Because the majority of Pokémon species have a 50/50 gender ratio, a typical female Pokémon cannot have an Attack IV greater than seven (corresponding to the 0-7 IV range). In later generations, female Pokémon do not have these restrictions.
- Although its English and French names suggest that it is exclusively male, Mr. Mime may be of either gender.
- Since Azurill is 75% female, 1 in 3 of every female Azurill will change into a male upon evolving into Marill (based on Azurill's personality value) because unlike Azurill, Marill is 50% male and 50% female.
- In the international versions of Generation II, due to how the battle field is programmed, Nidoran♂ and Nidoran♀ have their gender icon shown twice, in their name since it's part of it like in Generation I and another after the level number. It should be noted that this does not occur with the Japanese or Korean versions, due to the icon appearing after the Pokémon's name, thus avoiding redundancies.