A Pokémon that is infatuated cannot attack it 50% of the time, even against Pokémon other than the one is is infatuated with. It is caused when Attract is used on an opponent of the opposite gender, may be caused when a Pokémon makes contact with a Pokémon with Cute Charm of the opposite gender, and is caused to the target of the infatuation when a Pokémon holding a Destiny Knot is infatuated. Pokémon with the Oblivious ability are immune to infatuation. Infatuation cannot be passed with Baton Pass. Infatuation will end as soon as either the affected Pokémon or the Pokémon it is attracted to is removed from the battle.
http://bulbapedia.bulbagarden.net/wiki/Infatuation#Infatuation
