If you are comparing apples to apples, i lean toward that opinion myself. Vs comparing apples to oranges- a factory comprised of mostly women, making low wages, but in a comfortable environment, to a factory where mostly men work in extreme temperatures, no AC, poor work conditions, but receive higher pay.
It would be interesting to follow a man and woman hiring into the same job, both performing equally, moving through the ranks, receiving performance raises, etc, over 5+ years.
That's not necessarily sexism or anything. I can regale you with tales of woe of guys I know from where I worked that had reasonably equivalent jobs and a few get ahead (while being less competent and accomplished) and others that were far superior never went anywhere. There's much more to this than your sex. I'm not saying it's never been or that it probably doesn't persist anywhere these days. But life's not fair. Some people get ahead because they're really good and some people get ahead because of who they're related to, they go to the right school/church/clubs, they play the games, etc even if they can't manage their way out of a paper bag. And still, some others, perfectly capable and hard working, are pigeon-holed or forgotten.