In contrast, women receive fewer than 50 percent of undergraduate degrees in math and only 15 percent of those engineering, which would lead to higher paying jobs. New educational achievements have resulted in women's advancement into different occupations over the past quarter century. Women represented about 16 percent of economists 1970, and over half in 1997. Still, affirmative-action supporters such as Eleanor Smeal of the National Organization for Women and Mary Becker of the University of Chicago note that some occupations still have fewer than ten percent of female workers, and they cite this as evidence that discrimination persists and that affirmative action is still needed. But many of these jobs call for substantial amounts of physical strength and are risky and dirty, such as mining, timber logging, construction, firefighting, and welding and cutting.
Some jobs also call for odd hours of work, such as truck driving.
Railroad transportation, as well as having unusual hours, is also a declining industry. Women have broken barriers to entry into so many more competitive and high-paying fields. A good case can be made that women have not gone into these lower-paying, dirty trades by choice, rather than due to discrimination. This story would not be complete without some mention of the role of childbearing. Census data show that approximately 80 percent of women bear children at some point in their lives.