I've seen a number of studies showing that women are, on average paid less for the "same work." To me, this doesn't make sense because as a whole, women don't do the same work, work fewer hours, leave for years at a time, etc. But are there any studies to confirm that these are the real reasons? I'm never quite sure how to respond to this point in conversation. What are the real explanations for the pay discrepancies that have been found?