How do convince your parents who hate cats to let you get one?

First I would figure out what it is they don't like about them, and why they don't want to get one. This may sound cliche, but taliking to them is the best way. Try and come to an agreement. Maybe you can get a cat, but must pay for food cost and take care of it, and they can pay for vet cost and the actual cat itself. I think really your best shot is to explain why you want one. Tell them that you'd like to talk about it, and you don't understand why you can't have one. Be reasonable and calm, and if you listen to their views, they are more likely to listen to yours too.

Good luck, and I hope you soon have a furry friend in your future! :)