>>514159684
It's a federal law (and states have similar laws) that you can't buy a firearm if you are "adjudicated as a mental defective", I don't exactly know how a "court, board, commission, or other lawful authority" could make gender dysphoria a mental illness, but the law doesn't really state what the mental illnesses covered are. It's seemingly up to the "court, board, commission, or other lawful authority".