Help coming out to parents for 3rd time?

Hey,

So I, as you can see to the title, have come out twice to my parents. Both times, my father told me to not identify as anything other than straight because "I'm still half straight". My mother has both said that my "confusion" was a side effect of my hormonal disorder and medications to treat it, and that she "doesn't care", but would be ashamed of me if I was out to everyone, because apparently... That's tactless.

As a (mostly) out teen, I just want them to realize that my "alternative" sexuality is nothing for them to freak out about, dislike, etc., but don't know how to do that. Is there anyone who can help me come out to them successfully, with ideas as to why they feel like this, and how to make my sexuality feel less imposing to them?

Thank you so much. (*hug*)

~Sunshine