There is a good mix of men and women, although the latter do outnumber the former slightly. Most NIU students hail from middle class households, which means you don't run into a lot of spoiled brats on campus. There is a sizeable gay population, but they aren't as visible as perhaps they could be. Politically, most students are liberal, but there are a growing number of students who are quite proud to be conservative.
Like many Midwestern universities, NIU could do better when it comes to diversity, but it still earns a high grade for how well various ethnicities, orientations, and backgrounds are represented and treated. It never feels like the student population is 70 percent white. Instead, cultural groups like the Black Student Union do an excellent job of making themselves visible, and resources like the Center for Latinos and Latin American Studies help by improving retention rates. In fact, students that come from largely white high schools might find themselves in for a big cultural shock as they adjust to their surroundings. But diversity is an essential part of the collegiate experience and a very healthy thing to be exposed to. And make no mistake, you will meet several people who look and act different than you right away on your dorm floor during freshman year.