"The .69/dollar claim is as old as time, cited all over the place. Has nothing to do with any external factor like hours, experience, etc.: it demonstrates that all other things being equal a woman is paid less for the same work."That's just not true. That statistic ignores all other factors such as hours of work per week, experience, danger, and a host of other factors. It quite literally compares the salary of people with years of experience who are working 60 hours a week directly with new hires of the same job title who are working 40 hours a week. It lumps them all together. The 76 cents (or 72 cents or X cents) on the dollar myth has been debunked very thoroughly, though it still enjoys popularity amongst feminists.
Study after study which has actually controlled for factors such as experience, hours worked, travel required, etc have found very little pay disparity. There are a number of more forceful articles on the subject on BW, the Cato Institute and other similar sites. This NCPA article is a gentler explanation of The Wage Gap Myth:
http://www.ncpa.org/pub/ba392