Most of these effects go away once you adjust for years of experience and the job.  The latter is far more important than the former. 

However, the 77 cents headline gets attention, even though it does not stand up to careful examination.  This is not to say that women don't face discrimination and challenges, they do, serious ones, and they also bear a disproportionate burden making sure the human race continues, but consistently being underpaid to that degree is not supported by the empirical evidence.