We had these mandated to our building over 20 years ago by the administration. What happened was the women absolutely hated the idea that men were using the same restroom, so after 3 weeks of complaining we wound up delegating which restrooms were exclusively for women and which were for men even though the signs said otherwise. The first thing you learned when you were hired was which bathroom to use.
The subway system in Boston had a guy that permanently bended his gender. The women didn’t want s/he in their bathrooms, and the guys didn’t want to be blamed for any “sexual harassment panda” graffiti, so they built a third bathroom, just for him.