http://www.ana.co.jp/eng/aboutana/press/index_sm.html
This will be available on all international flights by end of April except on A320 and B737 flights...
Men are only allowed to use this lav under the following circumstances.
- When required for safety reasons, just prior to the seat belt sign being turned on during take-off and landing.
- When a passenger is not feeling well and a personal emergency requires such use.
- When there are very few female passengers and the women-only designation has been lifted for the flight.
*An in-flight announcement will be made in such cases.