All that's really new in recent decades is the widespread use of ‘they’ for a specific singular antecedent of
known nonbinary gender. The word itself has been consistently attested for nonspecific
singular antecedents since the 14th century (when English was barely recognizable to us as such!), and if you're telling a story today about a
specific someone
whose gender you don't want to reveal, ‘they’ is the pronoun for that. —
Squeamish Ossifrage 1 hour ago