Agency was the first entry in this category of writing about character-based issues. Bechdel test was an easy and related follow-on. Now the entry that, of all 26 letters, probably fascinates me most.
My adventures in writing revolve around a series of books that in turn revolve around the lives of a river guide on the Salmon River and a rancher who grew up on a ranch in the nearby Lemhi Valley. River and Ranch is the first book I've written but is the 7th +/- in the series. New Grass Growing is next in that line.
Back in the day when this idea of writing started to take hold, my kids were little. Those kids are three daughters. My wife and I were aware of them being every bit as active as the boys they knew and that lived in the neighborhood. The conscious realization of this was letting the girl "stuff" happen as they each discovered it, but also stressing "girl power" when we saw them in circumstances where we wanted them to be aggressive and "not back down", for lack of a better way to explain it.
That parent-based setting was the dawn of my awareness of strong female characters. The first thing I realized is that no matter how much we put "blue" stuff in front of our daughters, they all gravitated to "pink" stuff, without any dis- or en- couragement from either of us. My take away from this is that girls are different from boys. From day one. AND They are strong in their own way, unlike male connotations of strong, but strong nonetheless.
As a writer I find that significant, because the easy tendency when writing strong female characters is to put the woman in man's clothes and have them fight alot with swords or guns, etc. In other words make them like male characters, since strong is an adjective associated with men. For some characters in some stories that just might work. But for other characters and stories that "change of clothing" and a girl name likely will not.
As I have gradually drawn out the plot and the world in which my MCs live, the big thing I've come to realize is that too often female characters are in a book to fit the plot of another, often male, character. They are dependent on events written for that male character, such that the female MC is reacting to something happening to the male MC. This is, in part, what led to the Bechdel test I think. I want my fiction to be populated with women on their own plot line. Both plot lines intersect, boy and girl do meet and fall in love, but that ranch woman has her own story with her own set of subjects.
This could go on and on. I find this subject fascinating in many ways both good and bad. If it interests you, the three articles below go a long way towards maturing my thought process on this subject. I still read and reread them. They might change your outlook on female characters as well. cheers.