Would An Extra $10,784 Help Your Family?

[Spike89]

20. But, that is not how the stats are compiled

I'm 100% behind equal pay and gender should have no bearing on pay. However, you are correct that an E-5 salary is an E-5 salary whether you are a man or a woman, but it is a lot more complicated than that. The military is an excellent example, but for both ways of looking at the issue. An alternate method would be to average all the male salaries paid in the military and compare that amount to the average female salary--You'll probably find a "pay gap" pretty close to the national average.
There are at least 3 huge variables in the gender/pay issue and solutions aren't as easy as mandating equal pay. The first variable is very contentious, but lets stay with the military example for consistency. My arbitrary 1st variable is job/career selection. Base pay may be equal, but there are extra benefits available for soldiers in active combat areas--there are limited opportunities for women in combat areas compared to men. In the civilian workforce, an analog might be the high-paying jobs on a crab boat in the Bering Sea--no one denies that the jobs are dangerous and very physically demanding and therefore should pay well. There may be discrimination in hiring for those crab boat jobs, or it might be that women are too smart in general to risk themselves in that manner for a few dollars. More subtle, the same dynamic is seen in education (an area where pay grades are generally standardized like the military). More men (per capita) pursue administrative jobs within schools, they also tend to gravitate toward the higher grades and specialized curricular areas (where pay is higher. Women, for many reasons, dominate in the lower-paying elementary classrooms.
A second variable is probably as contentious--leave of absences. The military, live civilian employers must grant leaves for pregnancy. Men and women can both qualify, but women tend to take longer leaves (understandable) and a significant number choose to not return to the workforce when they've exhausted their leave. In the military, they don't care if you are 19-years old with 2 years experience, or 23 with the same experience--you are both probably the same rank/pay scale. By the time the 19-year old becomes 23, if he or she hasn't taken a maternity leave--they will almost certainly outrank the 23-year-old who took time off for a family. It doesn't matter if you are a man or a woman--taking a year or two away from your career in your 20s will put you maybe 3 years farther behind your peers.
Value discrimination. It is really a second-level discrimination event but really tough to get a handle on. This may happen in the military, but is more common in the civilian world. "Traditional" female careers are typically paid less than traditional male careers. Comparisons are difficult and assigning values is hard, but the classic example is nursing pay vs. doctor's pay. A male nurse probably makes the same salary as a female peer and a female doctor probably earns the equivelent salary as her male peers. However, because most nurses are still female and most doctors male--there is a gender gap in pay. Maybe it is more difficult to become a doctor, maybe there is more pressure/responsibility--but the question is how much should the differential be and how much is the current differential colored by gender issues?
The simplified "women make .70 on the dollar" stats are alarming, but there is a lot more to the topic of fair pay than most people are willing to admit. The military example is very good in that it is very easy to show women have pay parity and just as easy to show that men get paid considerably more on the average than women. Once you realize that, you begin to see that the issue is almost as difficult to frame as it will be to fix.