Sexuality, I came out as gay
I'd be bluntly honest to them. Or play the sneaky hand. While mostly in today it's all about sex, sex and sex, play the love hand. Because you're gonna fall in love eventually. (Maybe o.o)
"There's nothing wrong with me simply LOVING someone of my own gender, is it so bad? It's not bad morals to love, it's part of who I am, and I can't change that, I'm your child and I don't want my family to neglect and hate me over who I am, you've been with me and raised me through out everything in life this far, nothing about me has changed, I'm still the same person, just who I'm going to be with isn't going to be to your expectations, and that's no ones fault nor is it a bad thing."
But while parents do raise and are responsible for you, they won't always be in your life sadly, you will go out and make your own life, your own family of friends and people who are special too you. So while it may be hard now, the future is always something to look forward too.
Something along those lines. It will take them a while to accept, as it didn't come out in the best of circumstances to begin with. If at home it gets too bad and upsetting go to a friend like someone else suggested for a few days to let them clear their heads.
Over all it's their loss, and I'm sorry for your turmoil.