Any attempt to compare wages by gender must also factor in years on the job and job performance.
"equal pay for equal work." Two people with the same job title are not doing necessarily doing equal work. One could be dedicated and pumping out twice the results of a slacker, and it should be expected the performer is paid more.
In Federal Gov't employment, there are counter-productive rules that prevent rewarding performers. Low Performers cannot be penalized and must be paid the same wages as High Performers. The Federal Government Employment policies cannot be applied to the private sector without destroying America's labor force and our competitive standing in the World.