You may recall hearing that there is a wage gap, usually something around 27 cents on the dollar. That is the difference between median wage earners, not men and women with comparable qualifications working comparable jobs. Once you take into account things like education, experience, hours worked, and years of continuous work, the gap drops to a few cents (depending on your regression). The remaining difference is explained by the fact that men are stupid.
Men are more likely to sacrifice quality of life for a higher wage. Men take jobs with longer hours, in worse working conditions, and with a higher risk of being killed. Women tend to prefer flexible scheduling, comfort and convenience in the workplace, and fringe benefits. Ask 20 men and 20 women how much they would need to get paid for (1) an additional 5% risk of getting maimed this year and (2) to work without air conditioning, and see which sex comes back with the lower dollar amount. If you said, “My job doesn’t have air conditioning,” you are probably male, and you took the money.
Note which of those things above are taxable. Just one: money. You paid for your new video card with after-tax dollars; the hours you spent earning those, your female equivalent was already logged in and leveling her warlock, tax-free. She found some crafting components while leveling, which you bought at the auction house with gold you bought from a farmer. She won twice before you started playing.
Men are helpless slaves to the big number, the shiny object. You are grinding for hours until you cannot see, while your wife has a good time laughing with people at the tavern. When the raid starts, they will take her over you because she plays a healer. She won twice again.