They're minors. If by major you mean college graduates, they should make more than children. If they are in college, I can understand.
They could be saving for college their could be a lot of reasons they need money. It isnt like the jobs minors can work are makin it rain anyway. Up to a certain point age discrimination is not ok. This is one time where it crosses the line.
Why is this even a debate? What authority does the government have to tell people how to run there businesses?