A few years ago, at a local writers meeting, I once listened to the beginning of a story by one of the male participants--a story about a young woman dealing with her family's vagaries. The best character in the scene was male—the brother of the protagonist--with a strong personality and interesting dichotomy of emotions. I wanted to know more about him.
After general critiquing, I asked the fledgling writer why his protagonist was a young woman--in fact, why all his stories were told from the point of view of young women or girls. He responded that he had read that most of the readers in the country were women and, therefore, thought his character selection would give him a chance at a greater audience.
Whoa! I and others in the group quickly pointed out that while the majority reader gender might be female, it didn't mean they only read books about or by women. If that were the case, all those action/PI/thriller male writers should just pack it in--they'd be doomed. Not to mention the myriad male mainstream and literary writers who don’t write from a female point-of-view.
I wonder how many writers of fiction think first about their audience and try to craft a story that will fit? I suppose if you’re aiming for younger readers, that might be important, but for me (and I’ve written for young readers and YA titles, too), my main stimulation is a compelling story or situation, where the protagonist's reaction and influence on the story line is believable. I don’t know if I could honestly develop that, if marketing was my primary thought.