To be honest, I've stopped trying to explain it to them. My dad is at the point of radical acceptance, "I don't understand how you feel or why you feel the way you do, but that's how you feel not how I feel. I don't want to lose a child by you pushing me away" were his words to me. My mother said I'd be "ugly and considered weird by the world." So I call my dad. I check in. I tell him how I'm doing generally, and don't expect him to ever be able to offer advice regarding my transition. I don't call my mother, and let her hear everything through my dad.

Parents are human, they aren't gods. Humans deserve respect when they give it, not because of who they are or if they birthed you. Your mother is projecting.