Yes it is,it's called Gender Dysphoria. When a person doesn't feel right with the gender they're assigned at birth, so they feel the need to identify as something else. This is a real mental disorder.
THE BEGINNING OF HUMANITY TO THE YEAR 2000:; Male or female! VS NOW FOR SOME REASON:; OMG ARE YOU ASSUMING MY GENDER??? HOW DID YOU NOT KNOW I IDENTIFIED AS A WOMAN??? BC YOU HAVE TESTICLE