Perhaps it is due to "family costs" being carried disproportionately by women.
Leaving early to pick up kids, staying home when kids are sick, etc. Even though typical gender roles are becoming less typical, they may still result in differential output from the perspective of an employer.
Thomas Sowell (a while ago) showed a dramatic difference in salary between all women, and women who had never married, suggesting that a huge component of the pay gap was due to household and family expectations.
I imagine there is more recent research on this exact theory, but I'm not aware of it.
But if a man earns enough to pay for the needs of his wife in addition to his own, that means he is paid much more than her. I wouldn't deduce that from the man's total compensation, since it essentially is an expense like any other.
Childcare / alimony is not an expense like any other because in many legislations you cannot really decided to stop paying that expense, see
e.g. [1]. In the US you typically go to prison pretty swiftly if you refuse to pay.
Leaving early to pick up kids, staying home when kids are sick, etc. Even though typical gender roles are becoming less typical, they may still result in differential output from the perspective of an employer.
Thomas Sowell (a while ago) showed a dramatic difference in salary between all women, and women who had never married, suggesting that a huge component of the pay gap was due to household and family expectations.
I imagine there is more recent research on this exact theory, but I'm not aware of it.