So, you compare a "starting" salary for a stock broker, with an RN. . .and you think you are denying what I said?
Now. . .look at the POTENTIAL for earning after, let's say, 5 years for both career, and the responsibility for both those positions.
In the other hand, the salaries for RN goes between about $40,000 to $78,000 (after 20 years!). . .and no bonuses!
Wrong about your zoo vs. childcare assumption as well. I wrote a lengthy paper while in college, and the reason some careers are so undervalued versus others is simpe: The "notion" that the caring career (nursing, social work, child care, teaching, etc. . .) is the "natural" state of women, so it is not really "skills." Also, because (and although women are now fully in the labor market), many people still believe that, in two income families, the woman's income is "the icing on the cake," and the man's income is the one who "put food on the table and a roof over the family's head" is still holding back women. So. . .in the case of the "zoo worker" vs. the "child care worker," the big difference is not how much more "difficult" (it isn't) or more "unpleasant" (it isn't necessarely if one choose that career and loves animals) the job is. . .it is just that caring for children is the "natural instinct of women" (supposedly!) and is not "real work," while caring for monkeys is "work!"
Thank God for Obama's bill for equal pay for equal job. . .which helps. Unfortunately, while careers are still overwhelmingly either "female" or "male" careers. . .the inequality in value assigned to those career will remain.