Metal is not always highly regarded - at least here in Italy - and It took me a lot of time to convince my parents that there was nothing evil in it. One thing that helped me is that I started from really "calm" genres - punk, hard rock - and than gradually switched to heavier styles, but nothing extreme. Now my parents accept it peacefully, 'cause they see Metal makes me happy. And my mom also likes some power ballads.

The real question is: how did your parents react when they discovered what kind of music you listened to? Or did themselves introduce you to metal?