Mark A. Schuster, M.D., Ph.D., Sari L. Reisner, Sc.D., and Sarah E. Onorato, B.A.
From the Division of General Pediatrics, Boston Children's Hospital (M.A.S., S.L.R., S.E.O.), the Department of Pediatrics, Harvard Medical School (M.A.S., S.L.R.), the Department of Epidemiology, Harvard T.H. Chan School of Public Health (S.L.R.), and the Fenway Institute, Fenway Health (S.L.R.) -- all in Boston.
One might have to go back to the era of racial desegregation of U.S. bathrooms to find a time when toilets received so much attention. Recently, several states have debated or passed legislation requiring people to use the public bathroom corresponding to their sex as "identified at birth" or "stated on a person's birth certificate." [1, 2] Some supporters of these laws have focused on the fear that male stalkers will claim to be transgender women in order to victimize girls and women in restrooms. Others have expressed vitriol and revulsion toward transgender people, describing them as "sexual predators," "voyeurs," and "pedophiles." Although transgender people have been characterized as dangerous, it is transgender people who have generally been the victims of verbal harassment and physical assaults when trying to use public bathrooms.
Opposition to the recent legislation has been strong in some sectors, with businesses, performers, and states voicing objections and canceling planned expansions, concerts, and government-sponsored travel. At the federal level, the Obama administration filed a lawsuit against North Carolina, asserting that the state's Public Facilities Privacy and Security Act violates federal law. It also issued a letter outlining the legal obligation of public schools to allow transgender students to use bathrooms that correspond to their gender identity. Eleven states have sued the administration over this directive.
Although these issues may ultimately be decided under civil rights law, bathrooms matter for health. Transgender people who are barred from using bathrooms where they feel safe might feel they have no choice but to suppress basic bodily needs. Delayed bathroom use can cause health problems including urinary tract or kidney infections, stool impaction, and hemorrhoids. Some transgender people even abstain from drinking during the day to avoid the need to urinate.
When transgender people are physically assaulted in public bathrooms, they may suffer bruises, broken bones, or worse. In addition, the ongoing fear of harassment and violence when using public bathrooms can take a toll on mental health. More broadly, laws like North Carolina's send a message that transgender people are not welcome in workplaces or schools, reinforcing the stigma, bias, and fear that fuel discrimination against transgender people.
Transgender people have a gender identity that does not match their sex assigned at birth, which is generally based on anatomical observation. Gender identity refers to an internal sense of oneself as being male, female, or outside these two categories (see table). Although representative studies of transgender people are rare, one estimate suggests that approximately 700,000 U.S. adults are transgender. 
Visibility of transgender people and support for transgender rights have increased dramatically in recent years. Media portrayals, once dominated by killers and comic stereotypes, are becoming more common, diverse, and authentic. In 2015, a total of 375 Fortune 500 companies prohibited discrimination on the basis of gender identity, up from 15 in 2002. Nineteen states and the District of Columbia include gender identity in employment nondiscrimination laws.
Despite these shifts, transgender people still face substantial discrimination. Beyond bathroom accessibility, discrimination is associated with increased stress, anxiety, depressive symptoms, post-traumatic stress disorder, substance abuse, and suicide. It is also associated with increased risk of bullying, verbal harassment, sexual assault, and nonsexual violence, as well as decreased health care utilization. Discrimination and its consequences are often most pronounced for those whose gender expression (how one expresses oneself in terms of culturally defined masculine or feminine appearance, clothing, and mannerisms) does not fit traditional, binary male-female categories, such as a person assigned female sex at birth who is taking hormones and has grown a beard but has not undergone breast removal surgery.
Gender affirmation -- having one's gender identity acknowledged and accepted in social, legal, and other settings -- can greatly enhance overall psychological health. The health care community can promote gender affirmation through clinical care, research, and advocacy. But there are challenges. Most clinicians lack expertise in transgender health, some resist treating transgender patients, and some make prejudiced and abusive statements. The 2008-2009 U.S. National Transgender Discrimination Survey revealed that 28% of transgender adults experienced harassment in medical settings, 19% reported being refused care, and 28% postponed care because of discrimination; 50% of those who received care reported having to teach their clinicians about transgender care. 
Transgender people need clinicians who can provide proper health care.  Clinicians can actively support their health by addressing the risk of verbal and physical assault, helping with emotional challenges related to disclosing gender identity to family and friends, and discussing medical options for gender affirmation (e.g., hormone therapy). They can support people who express a gender identity different from their sex assigned at birth, as well as their families, who may be confused and scared. Clinicians can also learn to address health care needs related to a person's anatomy regardless of gender identity (e.g., Pap tests for a transgender man who has a cervix).
Medical offices and hospitals can welcome transgender patients by, for example, adopting inclusive intake procedures and asking about gender identity on registration forms. Clinicians can ask patients which pronouns to use when referring to them and how to conduct a physical exam in a manner that will be most comfortable for them. If a clinician has not been trained to provide care to a particular group of patients, working with those patients can be intimidating. Education on providing health care for transgender patients can be integrated into clinical training at all levels.
Clinicians need to provide care to their patients using the best available knowledge. Although there are guidelines, protocols, and other resources covering health care to transgender people, a 2011 Institute of Medicine report recommended investment in more research on transgender-specific health needs. Open questions span topics from basic demographics and development to long-term effects of hormone therapy. There is more to be learned about general health as well as specific issues such as cancer risk, mental health, aging, and how best to support young people whose gender identity doesn't match their sex assigned at birth. This field needs skilled researchers, funding, and transgender communities open to partnering with researchers and participating in studies. Demographic and descriptive research would benefit from the inclusion of gender identity in population-based surveys. Further development of methods for identifying transgender people through surveys and claims data would enhance this work.
The medical community can continue to play a crucial role in advocacy, providing a key voice in legislative hearings and amicus briefs. Doctors, particularly psychiatrists, have been asked repeatedly to weigh in on the mental health of transgender people and on bathroom use and other controversies. In 2013, the American Psychiatric Association (APA) revised its guidelines to indicate that being transgender is not a mental disorder and that gender-affirming treatments are a valid focus of care for people who desire them; the APA has included gender dysphoria in its guidelines partly to cover people who have substantial distress or impairment and to ensure access to and coverage of desired medical interventions and treatments. The American Medical Association and other medical societies have called on clinicians to provide treatment to all patients regardless of gender identity and have advocated for insurance coverage of health care services for transgender people. In April 2016, the American Academy of Pediatrics repudiated North Carolina's public-facilities law. Physicians should not underestimate their ability to educate and reassure people who are misinformed and unaware or afraid of the unknown.
Establishing legal protection for transgender people in the United States may take time. Eliminating the need for such protection will no doubt take much longer. But being transgender, like being left-handed, may someday be recognized as merely another inherent human quality, no longer conferring a need for protection. In the meantime, the health care community can better address transgender health needs, help ensure that transgender people feel safe in seeking health care, promote resilience in the face of prejudice, and expand our knowledge of how best to promote transgender health and well-being.