In the countries that have gender equality, why do men get a higher salar than women even though they may have the same education, experience/skills?

Possible causes that are talked about: women are weak, gets pregnant and need to stay at home. Women get more days as maternity leave than father's get?

In some countries, a mother and father do share the same amount of parantal leave.

Is it fair or not that men get pays more than women for the same job.

This is for my school essay. Thats why I' m asking about gender equality and more. The work stuff is just an example i chose.
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According to Google, there is 8-10% between men's and women's salary. True or false? Why?
In the countries that have gender equality, why do men get a higher salar than women even though they may have the same education, experience/skills?
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