Replying to my own comment since this seems to have blown up.
Gender equality involves three interlinked questions:
1. As individuals, are women with a given level of education/experience/productivity *hired* at the same rate as men.
The answer is *no*, though economic forces alone will solve the problem even in the absence of regulation. Any business that can hire a woman who is just as effective as a man but will work for 80% of the salary will quickly find themselves making a lot of money. This leads to the next quesiton:
2. Are women with similar education/experience/productivity as a man *paid* the same?
The answer here is still "no", and we definitely need to change that. There are many reasons why, including "unfairness", "women arbitraging between salary and free time or other desirables", and everything in-between. Given the number of reasons, there likely isn't a single simple and fair solution. Google is big on gender equality, and it is just for them to do so. But gender inequality (ie, being able to hire a woman at 80% the salary of a similar man) has also likely made them lots of money. I'm not Google HR expert. Perhaps this is a non-issue there, but it is an issue elsewhere.
When the magical day happens and women are rewarded the same as men, there is still a third question:
3. As a *group*, are women (and men) allowed to reach their "equilibrium" in the workplace, or is it still dominated by men (or women)?
Even if women are hired fairly and compensated fairly, that doesn't mean there will be a 50/50 gender split in the workplace. Men and women *are* different. Yes, there are women who love welding, and there are men who love babysitting, but they are outliers.
No one knows what that equilibrium is, for IT or for any other field either. I don't *know* that 20% women in IT is equilibrium. It could be 50/50, or 90/10 for all I know. But it *could be* 20% too.
There's no good way to find that equilibrium via regulation. All you can do is set the conditions for fairness and inequality, and let the market find it's own balance. If there's a better way, I'd honestly love to know.