Gender inclusiveness in software companies is receiving a lot of attention these days, but it overlooks a potentially critical factor: software itself. Research into how individual differences cluster by gender shows that males and females often work differently with software for problem-solving (e.g., tools for programming, debugging, spreadsheet modeling, end-user programming, game-based learning, visualizing information, etc.). In this talk, I’ll present the first real-world investigation of software practitioners’ ability to identify gender-inclusiveness issues in software they create/maintain, using a method we call GenderMag. At the core of the method are 5 facets of gender differences drawn from a large body of foundational work on gender differences from computer science, psychology, education, communications, and women’s studies. Results from the field study were that software practitioners identified a surprisingly high number of gender-inclusiveness issues in their own software. We present these results and more, along with tales from the trenches on what it’s like to use GenderMag, where the pitfalls lie, and all the things we are still in the process of learning about it.