Different college majors require different kind of infrastructure. While humanities majors only need seminar rooms and libraries, engineering and science majors require expensive laboratories.
Several US universities consider charging higher tuition for undergraduates depending on their major - a system called "differential tuition".
According to the Omaha World Herald, 57% of 162 public research universities employ some form of differential tuition.
Some universities defend the practice of differential tuition by arguing that "studies where students will have strong earnings and the capacity to take on more debt, or where there’s a special case for investing more in a particular field" (from the World Herald).
Charging science and engineering students higher tuition could be counterproductive to encouraging more students to enter these fields.Should Universities Base Tuition Off of a Student’s Major? | Geekosystem