A commonly quoted statistic is that women make 77 cents for every dollar made by men, an accurate-if-you-overlook-different-work-patterns statistic. An article in Slate points out the true difference is more like 91 cents vs. one dollar, a much less glaring disparity.
Much of the initial disparity which disappears upon closer examination comes from men and women choosing different occupational paths. Men also put in more hours-per-week, travel more, and take less time off.
Is some small part of the balance due to discrimination? Probably, but that part is dramatically less than the 77 cents vs. one dollar figure implies.
What is particularly unusual is this article showing up in Slate, which is normally liberal or even "progressive." The article reads like something written for Forbes or The Wall Street Journal.