The Pew "Research Center, for example, did estimates based on hourly earnings of both full- and part-time workers and found that women earn 84 percent of what men earn. Why? According to Pew’s surveys, women were more likely to take career interruptions to care for their family, which can hurt long-term earnings. In addition, Pew noted, “women as a whole continue to work in lower-paying occupations than men do.” And last, Pew noted “some part of the pay gap may also be due to gender discrimination.” Women were nearly twice as likely as men to report that they had been discriminated against at work because of their gender."

I think it is unrealistic to think that in all cases the salaries will be equal for many different reasons.