The graph above outlines one of the most powerful demographic shifts of the past 50 years - and it hasn't really been mentioned too loudly (data from U.S. Census via Creative Class Blog).

The graph's a little hard to read, so here's what it shows: it's educational attainment by age (Americans only), cut to show which sex has a higher % of each category of education.  If you look at people age 60-64, people with masters degrees or higher are more likely to be men; the opposite for people without high school degrees.

The big story here is that this ratio has completely flipped over the past 30 years.  Amongst masters and bachelor degree holds, they're overwhelmingly female - and the trend is not about to let up.

And as for why this is significant: earning power.  The chart below shows earnings by educational attainment (age 21-64; data is a little stale - it's from '99; source here).  You earn 2.5x as much if you're a graduate degree vs. no high school - and that trends not about to change any time soon: