Hello Annie. Your post reminded me of this excerpt from Girl Decoded by Dr Rana El Kaliouby:

At AUC, there were equal numbers of male and female computer science majors, and this is true throughout the Middle East. Indeed, I was shocked to learn that in the United States, computer science majors, and majors in all other STEM (Science, Technology, Engineering, and Math) disciplines, are overwhelmingly male. In the Middle East, women actually outperform men in STEM subjects, perhaps because we have to work harder to prove ourselves.

AUC is the American University of Cairo, one of the best universities in Egypt. I find her experience similar to mine, but I see a discrepancy between the number of women engineering graduates and women engineers in the workforce, due to too many factors and a high barrier to entering the job market.

well, if you do some research in the field of cognitive psychology you´ll find this:

In 1997 Baron-Cohen developed the "empathizing-systemizing (E-S) theory" which states that humans may be classified on the basis of their scores along two dimensions (empathizing and systemizing). The E-S theory argues that typical females tend to score higher on empathizing relative to systemizing (they are more likely to have a brain of Type E), and typical males tend to score higher on systemizing relative to empathizing (they are more likely to have a brain of Type S). He suspects that if individuals with a "systemizing" focus are selecting each other as mates, they are more likely to have children with autism.

Ok?

So, this is the wikipedia page link (en.wikipedia.org/wiki/Simon_Baron-...)

This is related to the effects of testosterone on the brain, meaning, that this sexual hormone makes the right-part of the brain less dominant, while estrogens don´t suppress the right part of the brain. In this way, man are more left-hemisphere prone and thus more likely to be focus in 1 thing at a time. This is research related to sexual differences in cognitive abilities, which point to the fact that sexual hormones have influence over brain-cognitive functions

I know these things because prior to work as web developer I´ve went through almost 3 years of intense psychology college researching about these topics...

Your first and third points assume a cultural aspect that's very prevalent in many parts of the Western world. In essence, the biases that exist against specific genders in certain jobs (not just against women in STEM jobs, but also things such as biases against men in childcare or other people/emotion focused jobs) are a non-negligible part of why these types of gender inequality exist, but the very existence of these gender inequalities helps perpetuate those biases. It's essentially confirmation bias, but with a multigenerational feedback loop.

However, in other parts of the world, that bias either manifests in other ways, or the minorities there who the bias is skewed against are actively ignoring it and trying to get rid of it.

It's also important to consider though that being exposed to those biases as a child colors how one looks at their own life. Humans quite simply tend to subconsciously try to maintain what they view as the status quo. If you're a girl who's grown up exposed to the assumption that most engineers are guys, it's less likely that you'll consider going into engineering, though you probably would have to think a bit if asked why you didn't consider it (and would probably come up with some excuses other than "I'm not a guy."). If you pay attention, you can see the same kind of behavior in other minorities as well, even to the point in some cases of people essentially hiding behind their minority status as an excuse to not try and proactively improve their situation.

Hmm... I'm not sure, how do you explain the point 3? You'd think they'd be happier to stay in IT if that's their natural choice and now working and social environment improve (compared to their previous condition).

I personally think there are both reasons: inner/natural tendency and social environment that's behind the IT career choice by women.

Have you seen the documentary Code: Debugging the gender gap? What's interesting is that until the 80s computer programming was seen as good career for intelligent women. It wasn't until the 80s that computer programming was seen as a 'man's job'.

About the first topic, I don't disagree completely but one thing I realized is that, even though we traditionally associate developer roles to ones where you do not need to interact with people as much, it is not true for many companies. Of course you have a lot of coding involved as a developer, but many companies also want their developers to have people skills, since we have a lot of meetings during sprints, or we need to explain how we did things to our colleagues, and even interact with clients directly in the case of project managers who started as developers.

Read this book.