"A female Kirlia will always evolve into a Gardevoir," answered Shiranui, "A male on the other hand presents a very big decision.  A Dawn Stone will cause him to evolve to a Gallade otherwise he'll evolve into a Gardevoir as well.  Something to keep in mind if you have a male Kirlia is what style of battling you favour.  A Gallade's style of battle is similar to a Medicham thanks to the fact their types are exactly the same whereas a Gardevoir is more of a mentalist in battle—a style that is more typical of a Psychic-type Pokémon."