Hey,
It's hard coming out to anyone, even more so your parents. And it takes a lot of courage! So good for you for taking it on.
I was lucky in coming out to my mom, as she approached me because she had asked my sister if she knew anything about me and my sister wouldn't say yes or no either way: basically, she knew something was up. My Mom had always been somewhat homophobic (or so it appeared), she'd make remarks of un-acceptance when there were two gay guys on t.v., or other stuff like that. Not an extreme, but homophobic nonetheless. Her reaction to me telling her I was gay was different; she was incredibly apologetic and felt terrible for making me feel as though I would be loved less by her had I come out earlier. She basically has never known a gay man before me, and had no real person to base her opinions on, other than the seethingly archetypical stereotypes we see on t.v. She is now nothing but supportive and loving, and I couldn't really imagine her not knowing!
My father somewhat denied it at first; It was frustrating, because I felt like he was just not acknowledging who I was. But, I was persistent, and he finally came to understand that it wasn't a concious choice on my behalf to be gay, and that I am still his son no matter what. Both of my parents are now wholly supportive.
What i'm saying basically is, that one of the major reasons that parents may seem object to homosexuality (or anyone for that matter) is purely a lack of knowledge and exposure. Not everyone knows a gay person, and for some, it's hard to imagine someone that they know very well being gay. I say go for it regardless; what will happen will happen, and your parents do need to know if you want to truly have them be a part of your life.
Good luck! And be safe; hope it helps a little bit!
Sam