There is no shortage of things that inspired the creation of The Spitfire Club (the good work of The Campaign for Grade Level Reading, Brené Brown's research and storytelling, The Confidence Code, to name a few).
But a critical inspiration was The Bechdel-Wallace Test, a brilliant metric for female representation in works of fiction: It has to have at least two [named] women who talk to one another about something other than a man.
Children's books face a similar but different issue of representation that sends subtle, implicit messages to our children about the value of girls: Only 31% of all children’s books in print have a female central character [1]. Separate studies show that, since 2002, only 13% of children’s books in print are about people of color [2]. There are no known studies that measure representation of both gender and race/ethnicity. However, given these statistics, it's clear that only a small percentage of books feature both diverse and female protagonists. Which is pretty remarkable, given that, in the United States, people who do not identify as white comprise 38.7% of the population and women represent 51% [3].
Gender, racial, and ethnic identity isn't the only challenge: Add to this the reality that female characters in children’s books often lack qualities that most parents would hope to instill in their girls – strong female relationships, independence, resilience in the face of adversity, resourcefulness – the list goes on.
So what to do about it? Enter, The Spitfire Test:
The challenge for you: try to fill your child's library with as many "Spitfire books" as you can! It's good for girls, it's good for boys, and it's good for society to mainstream stories that show girls exactly how they are: half of the population, diverse, and tenacious, resilient, empathic, curious little Spitfires.
[1] McCabe, Fairchild, Grauerholz et al (2011) http://journals.sagepub.com/doi/pdf/10.1177/0891243211398358
[2] Cooperative Children’s Book Center, University of Wisconsin Madison (2017) http://ccbc.education.wisc.edu/books/pcstats.asp
[3] United States Census Bureau (2017) https://www.census.gov/quickfacts/fact/table/US/PST045217