DH was saying today how uncomfortable and bad he would feel if he was in a mixed-sex loo and a woman came in and clocked him with that look women do when they're suddenly alone with a male stranger and you can see the flush of panic in their face. It makes him feel shit that he's made a woman feel like that.
And while normally he would apologise/leave/cross the road/etc, there wouldn't be anything he could do in this situation.
His point was that the only men who are fine with mixed-sex loos are the men who get a kick out of making women feel uncomfortable. And those are the last men you want to be sharing loos with.