For every 100 dollars a man makes, 77 articles are published on bullshit statistics showing how women are oh so underpaid. If you've spent any time around TRP at all, you must have seen a dozen threads about it.
What you probably don't know, because there's a veritable dearth of articles published on it, is that there is actually a gender gap: the tax gap. Men, you'll be shocked to know, pay a massively disproportionate amount of taxes compared to women. But more than that, men pay a massively disproportionate amount of taxescompared to what they get back in government spending.
The data I'll use comes from a New Zealand study [PDF warning]. That's not because I'm a Kiwi but because, very unsurprisingly, gender tax gap studies are very hard to come by, due to how incredibly un-PC their conclusions are. I could find the raw data for the United States and my home country, but no elaboration as thoughrough as the one I'm going to present. I invite you to be as skeptical as you feel like and verify these conclusions for your country if you like.
So, first item:
This graph is pretty self-explanatory: at every point in his life, the average man will pay more tax than the average woman of the same age. In fact, from age 24 until age 65 (i.e. during the average graduate's working lifetime), the average man will pay more tax than the average woman in any age group. Only before beginning to work and after retirement are men surpassed in tax paid, and only by working women.
On to the next:
As you can see, once men hit graduate working age they pay more into the system than they get back, and only revert to taking out more when they hit retirement. Women, on the other hand, take out more than they put in all their lives, except for the 45-65 period (i.e. after they've stopped having and caring for young children and before retirement). Also, the net contributions by men are much larger than those by women: a 30-year-old man will on average give an average annual net contribution higher than a typical woman in any age group.
And for item three:
Those two decades of net positive contributions by women mentioned above do not come close to repaying all the tax money spent on a woman: on average, there's no point in a Kiwi woman's life when she'll be in the black towards her country. The average man, instead, pays his dues by age 40, and stays in the black unless he lives to be 85+, in which case he will be a little in the red. Still, even those men will cost a net cumulative loss of about $10,000; by the same age, a woman will have cost state coffers fifteen times as much.
Conclusions
I'll note that this was probably always the case throughout modern history; the difference between now and 50 years ago is that today men are no longer socially and institutionally recognized and rewarded for their larger role in sustaining the community, and are in fact berated and accused of discrimination even though they work more and contribute more than women.