A Gender wage gap exists, but not because of discrimination.
Women pursue lower-paying degrees
Women chose lower paying specializations within their fields
Women even when pursuing lucrative careers still choose lower paying jobs
Women work less overtime than men
Women take more time off, on average, than their male peers
Women are more likely to work part time
Women are less likely to ask for a raise, or negotiate their salary
Women are MORE likely than men to chose careers they enjoy
What it boils down to is this, a heterosexual woman seeking a mate will strongly prefer males in lucrative careers. However heterosexual males on the other hand, while they may still consider income of a female mate, it is not nearly as large of a factor for them. One study found:
"“For men there is no amount of income that the woman in the bottom ten percent in terms of appearance can earn to make men prefer her over women in the top 10 percent. That is, looks really matter to men relative to income. For women though, if the man in the bottom ten percent in terms of looks earns more than $248,500, they will prefer him over the more attractive guy earning $60,000.” http://bigthink.com/dollars-and-sex/
This effect is amplified in nations with skewed Male-to-female sex ratios. In China for instance, a survey from a popular Chinese dating website found that 72% Chinese women preferred a mate that had nearly double their own salary. In fact the gender wage gap is worse in China than it is in the United States. This creates a tremendous social incentive for men to aggressively snatch up all the high paying careers they can, and indeed that's exactly what happens. It is very unlikely the gender wage gap will go away without imposing draconian "Equality of outcome" policies, or re-engineering the social fabric of society. The gender wage gap is the result of the differing mate-selection strategies employed by the sexes, there is no fact in my OP that can't be explained by this reality.
Yes, I've been wondering about the statistics myself. I've met a lot of very capable females. However, I've also met a lot of girls that do nothing more than talk and utilize politics to pull nonsense and make a living.
However, I think if a women is capable and does her work above and beyond (regardless of her days off), that she deserves a good salary. Humans aren't robots, they need to break their schedule once in a while.
Many people are utilize politics to rise up the ladder, and this shouldn't be the case. Two people that are just as capable, should have equal salaries. Negotiation shouldn't be the key driver, since this simply comes down to sales pitches, not skills.