Playing With / The Smurfette Principle

Basic Trope: There's only one (important) female main character, and she (usually) exists solely to appeal to the female demographic.
Go back to The Smurfette Principle... But don't bring more than one woman with you! Girls Have Cooties, you know!
http://tvtropes.org/pmwiki/pmwiki.php/PlayingWith/TheSmurfettePrinciple