The United States women's national team has filed a wage discrimination complaint with the Equal Employment Opportunity Commission against US Soccer.
The moment the news hit earlier this morning, you just knew the responses would be predictable. One of the most common is "They should earn money proportional to what they bring in!" Another is "But the free market dictates what they're worth!"
Both of these arguments like to act as though sports exist in some kind of purely theoretical vacuum that can be used as an example in an intro to economics course.