Although I agree that you should have the final say, just remember that your parents are looking out for you. They also understand the world much better than you do, as cliche as that might sound. Often kids decide to study a subject based on their heart rather than deciding with proper reasoning. That's why we have so many people getting degrees in liberal arts thinking it'll make them happier, and all the work they can find is at Starbucks. Parents aren't like teachers or high school counsellors because they'll give it to you straight; they won't tell you feel-good things like "Follow your dreams!" or "Do what makes you feel good!". They know that just because your studying something you aren't absolutely fascinated about doesn't mean you won't be happy in the future.
Just remember, your teachers and school counsellors are wrong: your job isn't your entire life! You can study engineering, finance or medicine and get a well-paying job and you can study politics or philosophy or whatever your passionate about on the side!
Yes, I think parents should have some say in the selection of subjects that their children study. Students should also be involved in the decision making process, and they should become more involved with each passing year. Parents have the benefit of experience and maturity. Students are in touch with their subject and career interests; parents have to bear this in mind as well. As a general rule, parents try to offer sound advice. They can help with the difficult decision of which classes to take in order to best prepare for the future.
I mean they're not the ones going to the classes, if the child doesn't want to go to that class, he/she will probably not do their best, slack off and things like that. Parents can recommend, but at the end of the day, you should go for what you want.
Take into consideration, just for an instant if you must : your parents have more experience than you!
However, in-spite of that the only one who can decide what they want to achieve in their life time is none other than them themselves. Your happiness rides on you.Make it count.