We want to better serve the needs of three sets of people: transgender individuals, parents of opposite gender young children, and caregivers with opposite gender clients.
Our goal is for all city buildings to have at least one such bathroom in each of the ~50 buildings - subject to budget and physical constraints, and to see what can be done for commercial places with regulations and advocacy. One of the difficulties is that the state plumbing code spells out very specific requirements for number of Mens rooms and Ladies rooms depending upon the building capacity. There are lots of conditions associated with the code depending upon new vs. renovation, etc. In the City Hall Annex that was recently renovated all the bathrooms are single stall and have a men/woman/wheelchair symbol on them; it is probably violating the code. We are not talking about multi-stall gender neutral bathrooms as that would meet much resistance although a number of colleges are doing this particularly in their dorms. In the long run the plumbing code needs some modification; that won't be easy because of some of the people who for example caused removal of the public accommodation portion of the Transgender Rights bill that was recently enacted in Massachusetts.
The building code means for example that a small restaurant that has two one stall bathrooms can't label them both unisex without getting a variance and has to make them both handicap accessible. I was in a place with such a configuration a couple of months ago and I breezed into the men's room while there was a short line of women waiting their turn in their facility. A changed policy would be helpful to this situation as well, though there are some people who object to this because they complain that the other gender is too messy.
Some places have mens room(s), ladies room(s), and a single stall handicap bathroom. If the handicap bathroom has just the wheelchair symbol non-disabled people may feel they can't use it. Properly labeling would fix that. For example I went on a brief tour of the newly renovated Cambridge High school last week and in the Arts building on the bottom floor there was a boys bathroom, a girls bathroom, and a separate facility with a piece of paper that said "HANDICAPPED" taped to the door (it is interesting to go to newly buildings and in spite of all the glamor they have botched the signage either by omission or other means..