When you provide women the opportunity to become anything they want. They choose the careers that they choose. Which tend to me more social related careers. Teaching or nursing for example does not scale well; therefore salaries are limited.
Whereas men pick more "stuff" categories. It's men who work in STEM creating things. A car or an iphone is going to be generally speaking men who design it. These scale very well and salaries can be larger.
By these modern approaches that allow women to go into whatever they want to do. This is what creates the gender wage gap.