Cute Charm's out of battle effect is that if the Cute Charm user is leading the party, then wild Pokemon have a 2/3 chance of being the opposite gender. So if you are encountering a Pokemon like Combee (who normally has a 12.5% chance of being female), what will the encounter rate of female Pokemon be (assuming the Cute Charm user is male)?
Obviously this is of particular interest for catching Combee, as the males are completely useless.