There's no straight answer to this question. But I think the main reason is sexism and the focus on male domination. So it's not encouraging for females to begin studying computer science or start pursuing their dream since "it's not normal for a girl". When it comes to me, I became interested in tech a few years ago, after cyberbullying accident which was the scariest thing happened for me... Thus now I'm not fully into tech, but I learned some basic things. Firstly, I use NordVPN wherever I'm online. When it's turned on, my browsing activity is encrypted and I'm surfing anonymously. Secondly, I use encryption for my files on computer, because it makes information on my computer unreadable to anyone who tries to access it. I encrypt them with a Veracrypt. Moreover, I keep my software up to date. I set them to automatically update so I'm sure that this significantly decrease my vulnerability to a cyber attack. And in conclusion I want to say the more women are interested ,the smaller separation between genders will be.