What can you do if your parents don't approve of the career you want to take?

The best thing to do is talk to them. Have a genuine talk. Explain why you like or want this job, and what it means to you. Get them to say why they dont want you to take this job. Dont argue, and if its obvious that they cant be convinced(which if they realize that you really want this job, they should back down) remember that a compromise is an option.