My father and mother had a love marriage, but now they are against me chasing a boy I like. How do I tell them that it is not fair?

I think it's important to know their reasons for not being with you. Since they themselves had a love marriage, it seems difficult to believe that they would be against the concept of love marriage. You should sit with your parents and try to talk out the differences -- try to learn why is it that they are against your relationship. Is it the concept of love? Is it this particular boy? Or, are you spending so much time and energy on this relationship that you're ignoring your other priorities, e.g., studies? Please understand that parents always like the best for their children. It's understandable for parents who themselves had an arranged marriage to be against love marriage. But in your case, it seems your parents might have some reason behind their disagreement over this matter.