He or she can be whatever he or she wants to be. I honestly don’t care if he or she decides to be a cat. I simply choose not to participate in his or her delusion. If that makes me a jerk for relying on reality to determine what is fact and fiction, I suppose I am in fact a jerk.
Just because modern pharmaceuticals and medical procedures allow an individual to pretend to be something other than what they are does not make it so. Still, I seek no law that prevents individuals from making decisions about how they want to look or behave. Nor do I wish any harm on anyone for how they choose to look or act. I just expect not to have to bend reality to accommodate their choices.