Men's vs. Women's
Although the rules of the game are the same, the way that men and women play soccer differs on a physiological and psychological level. (Men are from Mars, women are from Venus, right? No? Moving on.)
Women's soccer matches tend to be slower because their lungs are smaller than men's, which means they receive less oxygen. Since both men's and women's games are ninety minutes long, women tend to slow down the longer they play (source). Weird, huh?
There are other physical differences as well. Because women are generally smaller than men, they have more space on the pitch and more room for attacking. On the flip side, female defenders have more trouble covering the entire penalty area. This means that there are more goals scored in women's games than in men's…like three instead of two (source).
Unfortunately, women's soccer doesn't receive nearly the same media coverage as men's soccer. According to the commissioner of the Women's Premier Soccer League, for every twenty articles on men's soccer, women get maybe one…(source).
Which is ridiculous because, particularly in the U.S., women's soccer has a much more successful track record than men's. The U.S. women's national team has won two World Cups (source) and four Olympic gold medals (source). There are also more opportunities for female soccer players in college.
There are 1,600 women's teams at the collegiate level (versus 1,400 for men) and the average athletic scholarship is $15,411 (versus $14,264 for men) (source). It's not a huge difference, but a notable one, especially when you consider how female athletes often get the short end of the stick.