Question about coming out to parents.

I believe this situation is fairly straight forward, although I don't know how to handle it.The Father: Seems ok with homosexuality. He is pretty traditional, although for the most part, liberal in social issues. He is ok with "civil union" although believes marriage should stay between man and woman. I also am under the impression that he would like grandchildren, but I think it would be different, because it's not traditional.The mother: Clearly against homosexuality, and has stated that she is not for gay marriage. She likely already knows, although I have actively denied that I'm gay (regardless of her frivolous attempt to find out). I haven't been ready to come out, and it's not happening on anyones terms but my own.The OP: I'm 18. I'm in the closet. I want out. I don't want to hide anymore, although at the same time, I don't want anything to happen between my parents and I (I am heavily reliant on them), although I predict that it is likely it could happen.Now there's the background (excuse it being primarily political, it's the only way I can think to talk about this in an comprehendible manner), and the questions I would like to present are:How would you determine if it were ok to come out? I would like to do so, but I have no idea how my parents would react.What are your thought considering the background I have presented? Specifically, what would you do if you were in my situation?If you require any further clarafication for anything I have said, please let me know. Thank you in advance.