It seems to be true, and nobody is disputing this, though there are many who take the trouble to explain the figure. They take a number of different approaches, but all of them seem to follow roughly this explanation given by economist Gary Burtless:
"Women have shorter job tenures than men because they have more work interruptions than men, usually because they have children and assume heavy responsibility for rearing those children," Burtless said.Worth noting as an aside that Burtless says that it is women who have children, ignoring the fact that they can't do this without at least some input by men. But there is a grain of truth here: a women's greatest productive capacity, her most important and indispensable contribution to society, lies in her ability to bear and raise children. This is a capacity that is not rewarded in the market place. A woman can spend her entire productive life raising a brood of children without receiving a cent in wages.
Now, when a woman wants to receive wages, she goes to the job market and sells her labour, typically at 77 cents to a man's dollar. Why is her labour discounted? As Burtless says, it's because of the responsibilities in fulfilling her role as a child bearer/rearer. At home, she receives no wages. In the market place her greatest productive asset is transformed into her greatest liability in gaining equality with men.
She's double screwed is one way to look at it. Or is it triple screwed? Twice figuratively, once literally.