When you want to practice boxing and your parents refuse, how do you communicate with your parents to let you practice?

In the United States: Dad, I want to box. Go ahead son, be like Ali and dance in the ring! In France: Dad, I want to box. Go ahead son, wave to the gold belt like a boxing champion! In China: Dad, I want to box. Hit, hit, hit, hit you to paralysis. Play all day without studying! Go away and study! Is there a future in boxing? What's so great about boxing? Can I go to college by boxing? Doing two more questions is better than boxing! So I saved up enough tuition to go to the club to train!