Women today are less than half as likely as men to work in excess of 50 hours per week. (Again, working women put in more hours at home.) It is rarer still for women to sustain that commitment for 20 years and then, without having burned out, increase her hours still more as a CEO. But exactly because it is rare, women who are willing stand out as more exceptional. Women, as it turns out, are far more 'European'—working to live rather than living to work. But the glass ceiling is rarely cracked by healthy, balanced people who work to live.

p. 82. - Why Men Earn More (2005)