My mother is the only one who knows. I'm only out to her because she asked me directly. I think that she'd spent some time processing the idea before she asked me about it, though, because there was a long, tearful, "I love you no matter what" spiel that came with it. Although, it did follow a conversation where she begged me to "tell her I wasn't trans."
I'm very lucky to have parents who supported me when I came out as bi, and who will stand by me when I come out formally as trans, probably. My mom reacted pretty similarly to both sets of news: a lot of tears, a lot of fussing that life will be hard for me, a little worry that it was her fault. Growing up in Iran, she sometimes has trouble with LGBT issues, but it's usually a good natured screw up, born of ignorance and not hate. A few weeks ago she even drunk texted me to say she "loved her little boy" which was mortifying, but extremely sweet.
I'm very scared to tell my dad, though. I know he won't disown me, but I think it'll be a lot harder for him. We've always been very close, and I've followed in his footsteps in a lot of aspects of my life. But a lot of our relationship has been rooted in the father/DAUGHTER thing, and he's so bad with change. He'll try to understand bc he loves me, but I feel like he'll deny it, pick it apart, and ignore any bits he doesn't like, just like he did when I came out as bi. He's the rigid, hyper efficient, structured type, and he doesn't like anything that doesn't fit nearly into boxes. Which I often don't, unfortunately. I'm supposed to be the Good Kid who always does things right, and I know he doesn't want a son.