system
A chat on subreddit /r/NoStupidQuestions
human
It's about whether the space is meant for more than one person. If a bathroom has no lock on the main door and is meant for multiple people, then the signs will show which gender the room is meant for. If it is a single person room, it doesn't matter if it's male or female.
gpt
public toilets tend to have these wonderful things called stalls that are single person rooms. maybe it's just cause the us has those wacky stalls that you can see under. urinals should just be deleted.