I have some gay couple friends who had a hard time with their baby because they don't normally have diaper changing station in the men's room.

This has been an issue since baby changing stations were first introduced, and it affects all men with children, or who care for children, not just gay ones. But I think the solution to that specific problem is to put baby changing stations in men's rooms too. Also, if this is such a big concern for men, and gay men in particular, it seems odd that they are not they campaigning for changing stations for all. Instead, all the gay rights orgs with their tons of money are championing trans, and trying to dismantle women's rights.

In the US the restroom situation is horrible. We need to move away from the whole stall door with a one in gap in the door and make more privet closet like rooms like they have in Europe.

Yes, perhaps. But whilst having all the toilets enclosed rooms with floor-to-ceiling walls and doors and no gaps would provide more privacy, it also might be less safe, especially in a mixed-sex setup. Too easy to push someone into such a room and abuse them without anyone knowing. Too easy for guys to place spy cams. Too easy for males using such toilets to use them for a wank - which guys already do way too often. Too easy for someone to pass out on the toilet and no one else to notice that she or he has fallen to the floor.

Also, in the US private, single occupancy toilets tend to be a magnet for drug users, who often hog them or take them over entirely. So what happens then is that the authorities or owners of facilities end up closing those sorts of toilets entirely, so that no one can access them.

A couple of years ago in London I got stuck in the kind of loo you describe coz the lock was defective and I couldn't get out. It was an accessible loo with a call button, but the button didn't work either. The door was so thick and heavy no one could hear my shouts. Thank god for cell phones, though it was more than an hour before I finally got through to the HQ of the the establishment to tell them I was stuck - and by then I was almost out of battery.

The other issue with the mixed-sex toilets is, as someone upthread mentioned, that males tend to pee all over the seats and the floors. Which means girls and women not only have to step in male urine, we'd have to clean off the toilet seat each time we need to use it. Since a lot of women hover and spray, I know we often have to do that already - but this would just make a bad situation worse.