Toilets and public restroom facilities are often what determines whether a trip will be pleasant or not.
This is not an issue confined to people with special needs, of course. Every human has the same input-output mechanism.
Formed in Singapore, the WTO is dedicated to "Clean, Safe, Affordable, Ecologically Sound and Sustainable Sanitation for Everyone". Sensible, practical, and increasingly successful in raising the issue of the need for toilets where there are people, this sounds like an organization with a mission for all humanity.
On the WTO's website there are links to member associations including the American Restroom Association and the British Toilet Association, to name just two of the 19 currently listed.
The WTO promotes its cause around the world. Its website includes resources for public education, and offers many resources, including some downloadable posters about how to keep a washroom clean.
The mission is broader than educating the individual member of the public. There are links and resources for sanitation system designers and operators, and for people who want to lobby for better public facilities at all levels.
The year 2008 has been declared the International Year of Sanitation by the United Nations. One of the UN's goals for 2008 is to reduce the number of people who do not have access to sanitation by 50 percent. If you support this goal, there is a petition linked to the home page of the WTO which you can modify, sign, and send to the leaders of your choice.
There are links on the WTO website seeking volunteers, and advertising various courses on aspects of sanitation and toilets. The many reference papers and studies linked to the website will assist people who want to persuade their local authorities to improve the quality and availability of sanitation.
Some member associations have activities you can get involved in. For example, in Britain there is an annual competition for the loveliest loo. Nominations close in late July.
WTO seems to be involved in every aspect of toilets and sanitation, whether it's in impoverished places with no toilets or places where there is lots of money but no apparent will to provide public facilities.
One area where the WTO is not comprehensive is in its membership. There are countries which one would expect to have joined WTO and yet there are no links to them on the WTO's website. One such is Australia. In the article Australia - Public Toilet Map there is a discussion of the National Public Toilet Map and the National Continence Strategy which brought it about.
Whether as a resident or a tourist, everyone deserves healthy sanitation.