There are other factors to consider as well, some of which are due to women's own preferences:

1. Women are often the ones doing the majority of childcare. I had a friend who was an intern in surgery, just as an example. She sometimes complained that men in her shoes had a wife who took care of the home-front but women were on their own. Same with many high powered careers - women still have to choose between career and home life while many men have a partner who is much more supportive.

2. Women often choose jobs with flexible hours partly for the reason described above. Men are therefore perceived as more dedicated to their jobs because they work more hours. However, this may not be tied to productivity - women often get the same amount done in 40 hours while men spread their work load out over 50 or 60 - so the men get credit for putting in the hours even though they spend a lot of the time just B.S.ing. Of course, there are careers where the long hours are actually spent working, such as in high end law firms. In those cases, it may be justified that men putting in more hours get the promotions. However, most of those men have a wife or gf who is the silent partner...

3. Men are more likely to take on dangerous or dirty jobs. This reason, actually, is the one that I think DOES justify higher wages for men in those positions. Who wants to work on an oil rig for months at a time? Or pick up trash, or work on a crab boat in Alaska or be an ice road trucker?

4. People still equate leadership with being "assertive". But when a woman exhibits the same level of assertiveness as her male counterparts, she's a "bitch". Meanwhile, if a woman is too pretty, men spend more time focused on her boobs than her brain, which of course affects the level of resect she receives. The double standards do still exist.

5. Women are more likely to choose certain professions that traditionally pay less. But this leads to the "chicken or egg" dilemma - are those salaries lower because women tend to fill those roles or do women gravitate towards jobs that pay less for various reasons? Interestingly, in 16th century Flanders, I believe, the guild that had the highest pay rates was made up of women - the lace makers guild.

One final interesting tidbit - single women make 90% of the money single men make. Meanwhile, married men make significantly more than their single counterparts, or at least that was the case several years ago when I read a study about this. Which sorta makes me think - the worst thing a woman can do for her career is to get married! And perhaps the best thing a man can do is to get married! LOL