The thing being overlooked here to some extent is that women's professions are, historically, devalued BECAUSE they are women's professions--and for no other reason.
Secretarial labor, when it was masculine, not only paid more than it does today but also could lead to a job in the executive suites. As soon as women were secretaries, the job became "pink collar" with little/no hope of advancement, and since then, people act like this is simply how secretarial work has always been.
Teaching in the United States has seen its reputation as a profession and its pay fluctuate depending upon whether men or women were the dominant sex in teaching. Women historically have been brought in whenever men cost too much, as a wage suppression tactic.
And just in case you think this is because capitalists always want to lower wages, think again. When computer programming started as a profession in the 1940s, women were the primary computer programmers. They were paid extremely poorly. Only after people started realizing what a big deal computers were did programming them start to fall to men--along with prestige and big pay increases for the new crop of male programmers who rapidly pushed out their female co-workers.
Nursing has been a profession much derided as feminine, and underpaid for a very long time. Now that men are involving themselves in nursing, it turns out the profession is becoming more respected and that men who engage in it are being paid more than women.
Make no mistake: the differential you're seeing isn't just random. It is one of the most pervasive forms of sexism in our culture. Children can see the ways in which feminine professions (whichever ones we've deemed feminine recently) are devalued while masculine ones are lionized. It's no wonder that little girl children sometimes ask to be boys because they want to play football--after all, googling for "my black child wants to be white" will bring up dozens of heartbreaking stories about kids who have already observed racial divides and know which side they'd rather be on.