I was diagnosed with Tourette's at 16. My tics arrived when I was either 7 or 8. I was labeled by virtually everyone. The labels weren't kind. The list of folks who didn't devalue me with a derogatory label is short. Most of those in my life who should have been on this list weren't. Receiving my diagnosis, my label, was a Godsend. It declared all the other labels wrong. Using any label other than "Tourette's" to describe me was officially ruled "unkind", "uncaring", "ignorant", etc. in society's judgment. My diagnosis removed me from the "freak" category and firmly ensconced me in the "sick" one. When you start at "freak", "sick" is a serious upgrade.
A diagnosis is a label that works for you. Humans give labels to everything. This is fact. Saying "I don't want to be labeled", or "I don't want my child labeled" is insanely naive. Make labels work for you. Societally, not all labels are equal. Some are considered immoral, some unkind, some complimentary. Diagnoses are a special class of label. They are unquestionable. If people choose ignore or diminish a medical diagnosis in favor of their chosen, generally derogatory, label, they render themselves socially unacceptable. They harm themselves, not the person they label.
Put bluntly, when I was diagnosed, those who had applied harsh labels to me because of my condition were forced to cease, or further damage themselves. In my case, it forced a number of people to serve as their own judge, jury, executioner, once "their crimes" were exposed. Only the most mordacious continue. My diagnosis conferred on me the ability to control how I am labeled.
I can't control the fact that I'm different, nor can I successfully hide it. I can, however, utilize social norms to make the worst of "the natives" behave.