Which game first allowed a female protagonist in the main Pokémon series?

Pokémon Crystal was the first main-series Pokémon game to allow players to choose a female protagonist.

Released for the Game Boy Color in Japan in 2000 and internationally in 2001, Pokémon Crystal is an enhanced version of Pokémon Gold and Silver. Players can choose either the male character Ethan or the female character Kris at the beginning of the adventure.

Gold and Silver introduced the Johto region but did not offer a selectable female player character. Crystal changed that feature while retaining the core story, Pokémon, and exploration structure of its predecessors. The game also added animated Pokémon sprites and a more prominent storyline involving Suicune.

Kris is distinct from later protagonists such as May, Dawn, and Serena, who belong to subsequent generations. The existence of female characters in Pokémon’s wider media before Crystal does not change the answer: Crystal was the first main-series game to make the player character’s gender selectable.