"Potty parity" is equal or equitable provision of washroom facilities for women and men within a public space.
Gender-neutral toilets are common in some contexts, including on aircraft, on trains or buses, portable toilets, and accessible toilets. In parts of Europe they are also common in buildings. In the United States, they began to appear in the 2000s on university campuses and in some upmarket restaurants. As of late 2013 Gender-neutral toilets are still limited to universities and some public restrooms.
Although gender-neutral toilets were introduced to the U.S. in 2000 it wasn't until 2013 that the state of California passed bill 1266("The School Success and Opportunity Act")also recognized as the "transgender bathroom bill" which enforces gender-neutral toilets at universities. Bill 1266 only targets a small group of the population in the United States. Most range from 18–24 years old 
Definition of parity
Parity may be defined in various ways in relation to facilities in a building. The simplest is as equal floorspace for men's and women's washrooms. Since men's rooms include urinals, which take up less space than stalls, this still results in more facilities for men. An alternative parity is by number of fixtures within washrooms. However since women on average spend more time in washrooms more men are able to use more facilities per unit time. More recent parity regulations therefore require more fixtures for women to ensure that the average time spent waiting to use the toilet is the same for women as for men, or to equalise throughputs of men's and women's toilets.
Women spend more time in washrooms than men, for physiological and cultural reasons. The requirement to use a cubicle rather than a urinal means urination takes longer; twice as long on average in studies. Women also make more visits to washrooms. Urinary tract infections and incontinence are more common in women. Pregnancy, menstruation, breastfeeding, and diaper-changing increase usage. The elderly, who are disproportionately female, take longer and more frequent bathroom visits.
A variety of modified urinals and personal funnels has been invented to make it easier for women to urinate standing up. None has become widespread enough to affect policy formation on potty parity.
John F. Banzhaf III, a law professor at George Washington University, calls himself the "father of potty parity." Banzhaf argues that to ignore potty parity, that is, to have merely equal facilities for men and women, constitutes a form of sex discrimination against women. Several authors have identified potty parity as a potential rallying issue for feminism, since all women can identify with it.
History and developments
Segregation of toilet facilities by race was outlawed in the United States by the Civil Rights Act of 1964. Provision of disabled-access facilities was mandated in federal buildings by the Architectural Barriers Act of 1968 and in private buildings by the Americans with Disabilities Act of 1990. No federal legislation relates to provision of facilities for women. The banning of pay toilets, beginning in New York in 1975, came about because women had to pay to urinate whereas men only had to pay to defecate.
In many older buildings, little or no provision was made for women because few would work in or visit them. Increased gender equality in employment and other spheres of life has impelled change. Until the 1980s, building codes for stadiums in the United States stipulated more toilets for men, on the assumption that most sports fans were male.
LP Field in Nashville, Tennessee was built in 1999 in compliance with the Tennessee Equitable Restrooms Act, providing 288 fixtures for men and 580 for women. The Tennessean reported fifteen-minute waits at some men's rooms, compared to none at women's rooms. The Act was amended in 2000 to empower the state architect to authorize extra men's rooms at stadiums, horse shows and auto racing venues.
In 2011 a "Right to Pee" (as called by the media) campaign began in Mumbai, India's largest city. Women, but not men, have to pay to urinate in Mumbai, despite regulations against this practice. Women have also been sexually assaulted while urinating in fields. Thus, activists have collected more than 50,000 signatures supporting their demands that the local government stop charging women to urinate, build more toilets, keep them clean, provide sanitary napkins and a trash can, and hire female attendants. In response, city officials have agreed to build hundreds of public toilets for women in Mumbai, and some local legislators are now promising to build toilets for women in every one of their districts.
On 19 February 2012, some Chinese women in Guangzhou protested against the inequitable waiting times. This movement has drifted to Beijing, calling for women's facilities to be proportionally larger to accommodate the longer use times and ameliorate the longer queues of females. Since March 2011, Guangzhou's urban-management commission has ordered that new and newly renovated female public toilets must be 1.5 times the size of their male counterparts. The aforementioned movement is pressing for the regulation to be applied retroactively.
In August 2014, Prime Minister of India Narendra Modi gave a speech saying in part, "Every school should build separate toilets for girls in a year so that our girl children do not leave schools," and "[i]t is a shame that our women have to wait for darkness to go out in the open to defecate." 
Current laws in the United Kingdom require a 1:1 female–male ratio of restroom space in public buildings. The International Building Code requires a 2:1 female–male ratio of toilets. New York City Council passed a law in 2005 requiring this in all public buildings. An advisory ruling had been passed in 2003. U.S. state laws vary between 1:1, 3:2, and 2:1 ratios. The Uniform Plumbing Code specifies a 4:1 ratio in movie theaters.
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