-Men go into technology and hard sciences more than women.
-Men are more likely to take hazardous jobs than women, and such jobs pay more than cushier and safer jobs.
-Men are more willing to expose themselves to inclement weather at work, and are compensated for it ("compensating differences" in the language of economics).
-Men tend to take more stressful jobs that are not "nine-to-five."
-Many women prefer personal fulfillment at work (child care professional, for example) to higher pay.
-Men are bigger risk takers than women, in general. Higher risk leads to higher reward.
-The worst working hours pay more, and men are more likely to work these hours than women.
-Dangerous jobs (coal mining) pay more and are more male dominated.
-Men tend to "update" their work qualifications more than women do.
-Men are more likely to work longer hours, and the pay gap widens for every hour past 40 per week.
-Women are more likely to have "gaps" in their careers, primarily because of child rearing and child care. Less experience means lower pay.
-Women are nine times more likely than men to drop out of work for "family reasons." Less seniority leads to lower pay.
-Men work more weeks per year than women.
-Men have half the absenteeism rate of women.
-Men are more willing to commute long distances to work.
-Men are more willing to relocate to undesirable locations for higher-paying jobs.
-Men are more willing to take jobs that require extensive travel.
-In the corporate world men are more likely to choose higher-paying fields such as finance and sales, whereas women are more prevalent in lower-paying fields such as human resources and public relations.
-When men and women have the same job title, male responsibilities tend to be greater.
-Men are more likely to work by commission; women are more likely to seek job security. The former has more earning potential.
-Women place greater value on flexibility, a humane work environment, and having time for children and family than men do.
This is from:
http://www.lewrockwell.com/dilorenzo/dilorenzo160.html