>>20
Discovery. Just as humanity grows in other areas and finds ways to categorize and define certain aspects of life and the universe, so does it also with society. It's not some big conspiracy, it's just certain aspects of behavior being defined more as we learn more about human behavior.
Though I may have qualms with the nomenclature, such as "disorder". I'd prefer them be called "distinguishments" because some aren't necessarily negative in their entirety and it gives reason upon society to look down upon you by being "disordered".