Since your parents doesn't like "your" music, they must have some tastes of their own.
Chances are, that their parents didn't like that either, just the way these things goes.

You say your'e 15. Part if the process of maturing, is getting more independent from your family. At least, theres not long untill nobody gets to tell you what music you can hear.
I agree with Peerless, noone should censor others musical tastes, be they parents or whoever.

Music has the power to do lots of things, but not to corrupt people.