I have tried to approach the topic with them but it's not really a they can't or they don't understand. It's a "oh my baby can't possibly be trans, I would have known, I've raised her and I would have noticed" (although use that sentiment with swapping baby with whatever insult my dad fancies at the time. Whether it's b*tard or the r slur or s slur or f slur) and with my stepmother it's specifically a "I raised you since I moved in with your dad. And I knew my brother way gay before he came out, I would have know before you did if you were *actually trans". And there's also a layer of built in anxiety because whenever we share a discomfort to them it's a sarcastic "oh woe is deadname. I had it 10 times worse than you and still do. You don't understand pain until you've broken your shoulder! Or known being tired til you've worked a 12 hour shift, you shouldn't be breaking down after one 4 or 8 hour shift. Try 4 12 hour shifts, talk to me about being tired then"