Pokémon species can have genders in few ratios. They can be also either only male, only female or genderless. All ratios are listed below.
the 3-digit Pokédex Number (e.g. 001, 054 or 239; but without # and mandatory with two zeros before!)
or the name of Pokémon (e.g. Pikachu or Rhyhorn, but starting with the capital letter!)
Ratios
1♀:1♂
These Pokémon have an equal chance of being either male or female. The majority of Pokémon fall under this category. Percentage ratio is 50.0% female to 50.0% male.
1♀:3♂
These Pokémon usually appear as male, but can be female. Percentage ratio is 25.0% female to 75.0% male.
3♀:1♂
These Pokémon usually appear as female, but can be male. Percentage ratio is 75.0% female to 25.0% male.
1♀:7♂
These Pokémon normally appear as male, rarely female. Percentage ratio is 12.5% female to 87.5% male.
Female only
These Pokémon only appear as female. Percentage ratio is 100.0% female to 0.0% male.
Male only
These Pokémon only appear as male. Percentage ratio is 0.0% female to 100.0% male.
Genderless
These Pokémon do not have any gender.