Facebook COO Sheryl Sandberg looks at why a smaller percentage of women than men reach the top of their professions -- and offers 3 powerful pieces of advice to women aiming for the C-suite.

And even in the non-profit world, a world we sometimes think of as being led by more women, women at the top: 20 percent. We also have another problem, which is that women face harder choices between professional success and personal fulfillment.