Homophobic parents... coming out.. sounds familiar. Well first off, think of which parent is the least homophobic, doesn't talk about it much, doesn't care too much, and tell them. Then ask them to tell the other parent. For coming out to anyone else, school, friends, siblings maybe, that should be normal, just say "hey, I'm gay" as a convo starter. The one thing that is most important is that it is on your own terms, don't come out if you do not feel comfortable with it or find the person untrustworty or anything. Personally, I have told my school, my friends, my online friends, and attempted to tell my mom (I wasn't ready at that time). My school is fine with it, so are all my friends, heck most of my friends are gay. I now feel more comfortable saying I am gay after telling people, and maybe sometime I will attempt my parents again.
