If you do the comparison within a given field and adjust for experience missed due to child-rearing, I would guess the disparity disappears.
What they're saying is that women who do easy office work should be paid as much as union construction workers or engineers.
Please cue the Internationale.
John Stossell (I think) wrote about this not long ago. You're right, it becomes statistically insignificant...
According to the language in this article, it doesn't say they compared pay for men and women head to head in the same jobs, it doesn't even say they compared those with the same level of education.
It just says they compared men and women who studied in the same fields.