Love Ball

Used by a trainer in battle : Attempts to catch a wild Pokémon. If used in a trainer battle, nothing happens and the ball is lost. If the trainer's Pokémon and wild Pokémon are of the same species but opposite genders, the wild Pokémon's catch rate is 8× normal.

“Poké Ball for catching Pokémon that are the opposite gender of your Pokémon.”