Perhaps the use of “her or she” would be better than they, when the sex is unknown.
Traditionally, “he” has been used when referring to an individual whose sex is not known. Then feminists began insisting on “he or she”, and it wasn’t long before people who thought that was cumbersome began using “they” in that situation. By now, so many people have been misusing “they” as a singular pronoun that some think it’s correct usage. It is not. “They” is plural, period.
The trouble is that English doesn’t have a widely accepted singular neuter personal pronoun for the third person. “One” sounds stilted, and “it” is used for non-human entities. People have tried to coin such pronouns, but none has caught on.
Oh well, the language does change; look at even Middle English. Sooner or later, this will become generally accepted if it’s not already, but not by me.
Like Latinx is better than Latino or Latina?
I don’t think so.