The gap between male and female earnings, although in a few countries narrowing somewhat in the wake of legislative efforts, has generally remained distressingly large, even for workers with roughly similar qualifications. It is now evident that this gap is due mainly to the concentration of women in the lower-paying occupations and industries rather than to men and women being paid differently in the same or similar jobs. Women are concentrated in the lower-paying occupations because these are sex-segregated keeping most men out, while the higher paying occupations tend to keep women out. On-the-job training to improve skills is biased towards males as well. Unequal pay for women is very evidently the tradition in many developing countries.