It's from the huge and complex social construct. I think this has been fairly well documented throughout the evolution of video games, specifically when you start looking at the golden era of arcades and games like Pac-Man (whose demographics consisted mostly of women).

With the home console revival and growth of PCs, games were marketed primarily towards young men as the default demographic. There's also the fact that what's considered for men vs women can vary drastically depending on whether we're talking about the US, Korea, Japan etc.