Male character function: be a character; Girl character function: love interest

When I was about 18, I was in a community theater production of Robin Hood. As is so often the case with theater, there were more girls than guys who auditioned, but there were more guy than girl parts in the play. I was one of three girls cast as a silent, hooded "Merry Man." During rehearsals it quickly became ridiculous. Though we kept our hoods on all the time, three of us girls playing Merry Men were really bad at walking and moving like men. I remember talking with the lead male actors.

Me: Why do all of the Merry Men have to be men? I could still be a girl and be in the band.
Actor: But if there was a girl in the band, why wouldn't Robin fall in love with her and not Marian? We don't want to confuse the audience.

I was confused myself. Why would that even be an issue? The presence of a single woman in proximity to the lead other than the Love Interest would confuse the audience? In real life, do guys go around falling in love with every girl who happens to be nearby? Obviously, I thought, Marian happens to be Robin's type. He must like the polished, noble, girlie-girl, and a Merry Girl would be rough-and-tumble. What's confusing about that?

But it is. As I look at movies, especially action movies and animated movies, there are rarely any girls besides the Love Interest. Audiences are accustomed to this. The main character's Love Interest can have an elderly female friend, or even a comic-relief female friend her same age (so long as she's overweight, extremely quirky, lacking classical beauty features, etc.). But No Extra Girls Allowed. It's as if the only function of a female character is to be the Love Interest. So if there are, say, two female characters then the audience will be confused. But wait, there are two! Which is the Love Interest? We don't know who to expect will end up with the Lead and the unexpected is upsetting!

Just when I watch a film that's an exception--like Thor, which had several female characters (though male characters still represented the large majority)--I think, hey, we're over it! Then I see 4-5 action or animated movies in a row with an all male cast and one token female--the Love Interest.

I want to be conscious of this. I want all of us to be aware. Because I don't want to see the reverse happen either. In an effort to over-correct, are we doing that with the boys? In YA novels, do we have female characters with 1 male character (The Love Interest) or two if there's a triangle? I'm begging writers of movies and books, be respectful of the girls. Include them in the stories. Girls can be funny and interesting and daring and shy and adventurous and evil and anything a character should be.