INTRODUCTION — Much of the care of men who have sex with men (MSM) reflects standards of recommended care of all men [1]. However, there are unique features regarding both medical and behavioral health of MSM of importance to practicing clinicians [2,3]. In addition, MSM may have particular concerns about access to care, insurance coverage, and the clinical office environment that should be considered as part of ensuring equal access to care [4,5].

Healthy People 2030, a document that outlines health goals in the United States, highlighted areas of concern regarding health care disparities impacting MSM and other sexual minorities [6]. In particular, MSM are at higher risk of HIV and syphilis. The Centers for Disease Control and Prevention (CDC) reported that in 2018, close to 70 percent of new cases of HIV in the United States were in MSM [7]. A record number of sexually transmitted infections (STIs) were diagnosed in 2018 in the United States, with over two million cases of syphilis, gonorrhea, and chlamydia [8,9]. The majority of syphilis cases were diagnosed in MSM. In addition, gay men across a broad age spectrum are more likely to attempt suicide, experience homelessness, and have high rates of tobacco, alcohol, and other drug use. Older MSM may face additional barriers to health due to isolation and lack of supportive services as a result of homophobia and stigma.

Despite identified disparities, education about the medical care of MSM is sorely lacking in medical education [10-12].

TERMINOLOGY — The population that has come to be referred to as "gay" in the West is not a descriptive term that would be recognized by all men who have sex with men (MSM). While LGBTQ culture is increasingly open and discussed, MSM consists of a diverse population that may respond differently depending on how communications in clinical settings are framed [13]. MSM are a diverse group with respect to race, ethnicity, religion, education level, and socioeconomic status [14].

Sexual orientation is generally thought of as having three components: identity, attraction, and behavior. "Gay" is generally used to describe how people identify themselves, while "men who have sex with men" (MSM) describes a behavior. It is important to recognize that “MSM” refers to a range of sexual behaviors and may not specifically reference anal sex. MSM may self-identify as gay, bisexual, queer, non-binary, same-sex loving, transgender, genderqueer, questioning, or heterosexual. Additionally, some who are just beginning to come out may experience a desire to be intimate with other men but may not yet have been sexually active with men or identify as being gay.

Some men may identify as belonging to a gender that differs from the sex they were assigned at birth. They may identify as transgender, using a term such as transwoman, or use a term such as "genderqueer," which blurs the gender male-female binary. Other terms are used around the world, but transgender is often used as an umbrella term to describe individuals whose gender varies from their assigned sex at birth. Transgender individuals challenge existing conceptions of “men who have sex with men,” as they may not identify as men nor have traditionally “male” anatomy. Care of transgender individuals involves both general primary care as well as consideration of behavioral, hormonal, and gender-affirming surgical care. It is important that primary care clinicians know whether their patients are transgender so they can manage these issues as well as preventive and other care related to natal anatomy, such as screening for cancer. Transgender men and women have unique behavior patterns related to HIV risk and their gender identity is entirely separate from their sexual orientation. For example, a transgender woman may identify as heterosexual because she partners with men, and a transgender man may identify as gay because he partners with men. (See "Primary care of transgender individuals" and "Transgender women: Evaluation and management" and "Transgender men: Evaluation and management" and "Sexual minority women (lesbian, gay, bisexual, transgender, plus): Medical and reproductive care" and "Lesbian, gay, bisexual, and other sexual minoritized youth: Primary care".)

Some MSM struggle with cognitive dissonance, stigma, and internalized homophobia related to their sexual behavior and may not identify as MSM or as any sexual minority. Some do not even consider same-sex or same-gender sexual activity to be sex at all. Stigma, oppression, and stress related to sexual desire, sexual activity, and sexual identity may affect the risk for sexually transmitted infections (STIs) and certain cancers. Understanding a patient's sexual orientation, including one's identity, behavior, and desires, all have a bearing on the ability to provide quality care.

PREVALENCE — Kinsey's 1948 study Sexual Behavior in the Human Male was the first report on same-sex sexual experiences among men in the United States (US) [15]. More contemporary studies suggest that about 3.5 percent of the United States adult population identifies as gay or bisexual, while higher percentages engage in same-sex sexual activity (8 percent) and an even greater number are attracted to people of the same sex (11 percent) [16]. The study, which also included surveys from other countries (Canada, Australia, United Kingdom, and Norway), demonstrated that 1.8 percent of adults in the United States identified as gay or lesbian, with similar rates in the other included countries, ranging from 0.7 to 1.1 percent.

In Gallup polls, persons identifying as lesbian, gay, bisexual, or transgender (LGBT) increased from 3.5 percent in 2012 to 4.5 percent in 2017 [17]. An estimated 10 million United States adults identify as LGBTQ. Among the millennial population (born between 1980 and 1998), 8.1 percent identified as LGBT in 2017 [17]. Contemporary studies of sexual minorities include genderqueer, intersex, asexual, and others, expanding LGBT to LGBTQIA+.

Regardless of the precise numbers, in the United States census figures confirm that "same sex"-headed households are widespread throughout the country. Such households were found in over 93 percent of counties in every state [18]. Thus, all clinicians, at least in the United States, should be considering "gay" or "men who have sex with men" (MSM) sexual behavior when seeing patients.

OBTAINING A HISTORY — It is common in United States medical schools to be taught, when taking a sexual history, to ask whether someone is sexually active, and if so, how their partner/s describe their gender; how many sexual partners they have had in the past year; and whether they engage in anal, oral, and/or vaginal sex. Patients should be told that the information related to sexual orientation is asked of everyone and has relevance to health care and prevention decisions.

Nonjudgmental questions about sexual behavior are valuable, although they may not identify those who have never engaged in same-sex behavior, but have the desire to do so. Unrealized sexual desires may be an important trigger for discussing issues such as related anxiety or depression, fear of "coming out," and concern about how this information in the medical record could affect potential insurance coverage or employment.

Additional questioning about concerns with sexuality or gender identity may help identify issues related to sexual health and concern about sexual function, as well as possible gender identity issues.

Providers should routinely ask the following questions to normalize sexually history taking for sexual minorities. Questions such as the following can be incorporated into routine screening questionnaires and can inform discussion and screening tests during a visit.

●"What is your gender?"

●"What sex was recorded on your birth certificate?"

●"Do you have sex with men, women, both men and women, or persons who are non-binary or of another gender?"

●“What type of sex do you have? Insertive anal (top), receptive anal (bottom), or versatile (both)? Oral? Vaginal?”

It is also important to ask about any history of sexually transmitted infections (STIs), including exposure to HIV (see 'HIV' below). For patients who identify as transgender, it is important to ask about medical transition (eg, hormonal therapy) and surgical history, which may affect sexual behavior and thus HIV/STI risk. For example, many transgender women report that after starting hormone replacement therapy, they struggle to maintain an erection. This may make them more likely to be a receptive anal sex partner.

ISSUES TO TARGET — There are few population-based studies of health issues in gay men. Based on clinical experience and epidemiology, we identify a number of areas in which clinicians providing primary care to gay men should provide additional emphasis beyond what they might focus on in heterosexual men. A 2011 monograph published by the Institute of Medicine that highlights studies of disparities among lesbian, gay, bisexual, and transgender (LGBT) people in general and gay men specifically highlighted that important issues to target include: HIV/AIDS; infectious diseases including sexually transmitted infections (STIs); cancer; immunizations; substance and tobacco abuse; behavioral health, mental disorders, and intimate partner violence [19].

HIV — In the United States, the overall incidence of HIV has decreased in populations of men who have sex with men (MSM) between 2014 through 2018, except in Native Hawaiian/other Pacific Islander MSM where an increase in diagnoses was seen [20]. Among Black MSM, the incidence and prevalence of HIV remains high; in 2018, Black individuals accounted for 42 percent of new HIV diagnoses in the United States, with 79 percent of infections among men related to male-to-male sexual contact. The high incidence among Black MSM is not due to increased unsafe sexual practices or drug use but is likely related to structural racial inequality, lack of access to prevention services and care, lack of awareness of HIV status, delayed recognition and treatment of STIs, and increased prevalence of HIV in Black MSM sexual networks, which all make the risk of any single sexual encounter greater [21]. Statistics from the Centers for Disease Control and Prevention (CDC) show that, of the 37,988 new HIV infections reported in 2018, 70 percent were among MSM, including MSM who use intravenous drugs. The highest prevalence of HIV is found among transgender women [22,23], who also experience high rates of STIs, discrimination, violence, and poverty.

While a combination of prevention activities seems most effective, key interventions are universal screening, treatment as prevention, and post- and preexposure prophylaxis (PEP and PrEP) using a harm-reduction approach that empowers patients to make informed choices and manage their risks [24].

In the United States, the CDC recommends that for effective HIV prevention [25-29]:

●Sexually active MSM can take steps to reduce the risk of contracting HIV, such as serosorting (choosing sexual partners based on HIV-status) or seropositioning (choosing sexual activities based on HIV-status) with men who are known to be HIV positive, consistent condom use, and, if HIV positive, letting potential sex partners know their status. (See "HIV infection: Risk factors and prevention strategies", section on 'Clinical approach to HIV prevention'.)

●For MSM who are HIV negative but at high risk, taking PEP can reduce risk after an exposure. The CDC issued guidance on use of PEP for nonoccupational exposures in 2016. (See "HIV infection: Risk factors and prevention strategies", section on 'Efficacy of prevention strategies'.)

●For sexually active MSM at risk, PrEP is recommended. PrEP guidelines were updated in 2017 [30]. (See "Administration of pre-exposure prophylaxis against HIV infection".)

●Health care providers and public health officials should work to ensure that:

•Sexually active MSM are tested at least annually for HIV (providers may recommend more frequent testing, for example every three to six months)

•MSM who are HIV negative, and who engage in unprotected sex, receive risk-reduction interventions

•MSM living with HIV receive HIV care, treatment, and prevention services

Universal screening — HIV screening has long been a core prevention strategy. Recommendations for universal screening are discussed separately. (See "Screening and diagnostic testing for HIV infection" and "Screening for sexually transmitted infections", section on 'HIV and hepatitis viruses'.)

Treatment with virologic suppression for all HIV-infected individuals — One of the major preventive benefits of HIV testing is the identification of individuals who are infected and are therefore candidates for antiretroviral therapy (ART). In the United States, ART is recommended for everyone with HIV, regardless of CD4 count, because it helps halt the progression of disease and prevents HIV transmission by lowering viral loads and making transmission to uninfected individuals unlikely. Studies have shown that risk of transmission of HIV from a virologically suppressed patient is essentially zero [31], prompting the “U=U” campaign (ie, undetectable equals untransmittable). (See "When to initiate antiretroviral therapy in persons with HIV".)

Use of barrier methods — For individuals who are uninfected, it continues to be important to counsel for use of condoms whenever there is vaginal or anal intercourse. There is a small risk of HIV transmission with oral sex, which is highest when an HIV infected man with a detectable viral load ejaculates into the mouth of someone who has open mouth sores. While it makes sense to inform patients that routine use of condoms can decrease the risk of HIV transmission, it is also important to recognize that many patients do not use condoms for sex on a regular basis and that, in the United States, there has been an increase in unprotected anal intercourse [25]. This suggests the need to consider recommending use of PEP or PrEP accompanied by ongoing counseling and monitoring for adherence.

Postexposure prophylaxis — MSM should be educated about getting PEP in the event of a high-risk sexual encounter, such as receptive anal condom-less sex with a partner of unknown HIV status or with a partner known to be HIV-positive with a detectable viral load. Repeated exposures suggest the need for additional counseling about risk reduction and consideration of PrEP. (See "Management of nonoccupational exposures to HIV and hepatitis B and C in adults".)

Pre-exposure prophylaxis — PrEP most commonly consists of using daily oral tenofovir-emtricitabine (TDF-FTC), along with HIV and STI testing every three months and ongoing counseling and assessment of risk at follow-up visits. PrEP has been evaluated in several large clinical trials in a range of high-risk populations, including MSM and serodiscordant heterosexual couples (ie, couples in which one partner is infected with HIV and the other is not). Overall, these studies demonstrated that the effectiveness of TDF-FTC is highly contingent upon medication adherence. (See "Administration of pre-exposure prophylaxis against HIV infection".)

Other sexually transmitted infections

●Prevention – Clinicians can play an important role in prevention of STIs by discussing risk reduction and safe sexual practices with patients [29]. Individuals need reassurance that close physical contact, kissing, and hugging are safe. While there is only a small risk of HIV transmission associated with oral sex, the same is not true for other STIs like syphilis and chlamydia. STIs are largely transmitted during oral, vaginal, or anal intercourse. Clinicians should spend more time on such discussions when there is a concern that a patient may have multiple sexual partners, has not been using barrier methods, has been recently diagnosed with an STI, or engages in drug use, particularly stimulants, while having sex. (See "Prevention of sexually transmitted infections".)

●Screening – Clinicians should perform at least annual HIV and STI screening for all sexually active MSM and transgender persons who have sex with men, except those in long-term (>1 year), mutually monogamous, HIV-concordant relationships [29]. Sexually active MSM and transgender persons include those engaging in any anal and/or oral sex. In addition to HIV, we screen annually for syphilis, genital chlamydia and gonorrhea, rectal chlamydia and gonorrhea (in those who have had receptive anal intercourse in the prior year), and oropharyngeal gonorrhea (in those who have had receptive oral intercourse in the prior year). More frequent screening every three months is warranted for MSM at particularly high risk for STIs, including those with multiple or anonymous partners. We perform one-time screening for hepatitis A virus (HAV) and HBV (with vaccination if susceptible), and at least one-time screening for HCV (table 1). This is reviewed in detail elsewhere. (See "Screening for sexually transmitted infections", section on 'Men who have sex with men'.)

Cancer screening — MSM experience increased rates of anal carcinoma. Anal carcinoma is more common in men with HIV, but it has also been found in those without HIV infection (table 2). (See "Classification and epidemiology of anal cancer", section on 'Sexual activity' and "Classification and epidemiology of anal cancer", section on 'HIV infection'.)

The putative cause is infection with human papilloma virus (HPV), which appears to progress through stages of anal dysplasia to anal carcinoma in much the same way as cervical HPV infection progresses to cervical carcinoma in women [32]. Certain subtypes of HPV appear to predispose more to this progression. A 2012 systematic review showed that there is a higher prevalence of anal HPV infection in MSM, regardless of HIV status [33].

Among MSM without HIV or other immunocompromised conditions, screening to look for precancerous lesions or cancer related to HPV infection is not universally recommended by clinical guidelines [29,34,35]. However, based upon the increased risk among this population, we advise screening all MSM for squamous intraepithelial lesions (SIL) every two to three years beginning at age 40. Screening for precancerous anal lesions is discussed in detail separately. (See "Anal squamous intraepithelial lesions: Epidemiology, clinical presentation, diagnosis, screening, prevention, and treatment", section on 'Our suggested approach'.)

HPV is also associated with oropharyngeal cancer (see "Epidemiology, staging, and clinical presentation of human papillomavirus associated head and neck cancer"). However, no special screening beyond that which occurs with routine medical exams and dental care is recommended at this time.

Immunizations — In addition to routine adult immunizations, we recommend that MSM who are sexually active receive these additional vaccines:

●Hepatitis A and B vaccines because both of these viruses are sexually transmissible [36,37]. (See "Standard immunizations for nonpregnant adults" and "Hepatitis A virus infection: Treatment and prevention" and "Hepatitis B virus immunization in adults".)

●Outbreaks and clusters of meningococcal meningitis have been reported among MSM in the United States (eg, New York City and Los Angeles) and Europe [38-40], and the Advisory Committee on Immunization Practices (ACIP) recommends that MSM receive meningococcal vaccination in the setting of such an outbreak. In addition, they recommend meningococcal vaccination for all adults with HIV. (See "Immunizations in patients with HIV", section on 'Meningococcal vaccine' and "Meningococcal vaccination in children and adults", section on 'Immunization of persons at increased risk'.)

●For all individuals, including MSM, routine HPV vaccination is recommended through age 26 to prevent HPV-associated malignancies. Use of the HPV vaccine is discussed elsewhere. (See "Human papillomavirus vaccination", section on 'Indications and age range'.)

Substance and tobacco use

Tobacco use — Smoking is more common among gay men than heterosexual men in the United States [41]. Younger gay men are smoking more now than ever. Clinicians should counsel and assist all patients with smoking cessation. (See "Overview of smoking cessation management in adults".)

Alcohol use — Alcohol use disorder is more prevalent among gay men in the United States than in the general population [41,42] and has been thought to contribute to some of the disinhibition that leads to riskier sexual behavior and exposure to HIV. Clinicians can often be the ones who first detect evidence of this issue through discussion. A multidisciplinary approach to stopping or reducing alcohol use is necessary. (See "Screening for unhealthy use of alcohol and other drugs in primary care" and "Approach to treating alcohol use disorder" and "Brief intervention for unhealthy alcohol and other drug use: Efficacy, adverse effects, and administration" and "Alcohol use disorder: Psychosocial treatment".)

Drug use — In the United States, drugs of abuse are not different among the gay populations than among others. There are, however, trends of drug use that do predominate in the gay community. According to a 2017 to 2019 survey, reported use of alcohol, marijuana, and hallucinogens were the most common among MSM; use of cocaine, prescription medications (ie, opioids, stimulants, and sedatives) and methamphetamine were less common but still increased relative to the United States general population [41,43].

Depending on what drugs are being used, these may lead to significant short- and long-term morbidity. The disinhibition associated with these has been one explanation for rising rates of STIs among MSM men [44-46].

Screening for substance use disorder is discussed in detail separately. (See "Screening for unhealthy use of alcohol and other drugs in primary care", section on 'Unhealthy use of other drugs'.)

The management of substance use disorders are also discussed in detail separately. (See individual topic reviews.)

Behavioral health and mental disorders — It was only in 1973 that homosexuality was declassified as a mental disorder. In 1986, the term "ego-dystonic homosexuality" was removed from the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). Several studies have identified higher rates of depression in gay men [47-52]. There also appears to be an increased prevalence of anxiety disorders, particularly in relation to a man's growing consciousness of being gay and struggling to come out [53] and coping with minority stress [54].

Although there has been debate about whether gay men are at higher risk for suicide, many studies show increased suicidal ideation and suicide attempts among gay men [55]. Rates are particularly high among gay youth; suicidal ideation and attempts are three to seven times higher among gay youth than among heterosexuals. Gay adolescents and men have also been found to have increased disorders of body image as well as eating disorders [56].

Despite the lack of clear data from solid research, the environment in which many gay adolescents and adults grow up, the violence faced by many at times in their lives, and the anxiety and fear during the process of coming out can leave emotional scars that often need to be addressed during adolescent or adult life. As a result, discussion of these and related issues is important and referral for counseling and/or psychopharmacologic intervention is often warranted. Many continue to struggle to come out and integrate a gay identity. Nevertheless, many gay men demonstrate great resilience and are able to incorporate a gay identity with no sign of related behavioral impact [57].

Intimate partner violence, sexual assault, and hate crimes — Studies suggest rates of intimate partner violence among intimate gay partners at approximately the same rate as among heterosexual partners [58,59]. (See "Intimate partner violence: Epidemiology and health consequences".)

Two striking differences are that informal discussions with survivors suggest that there is little screening done for this among gay individuals, and facilities designed to accommodate survivors of intimate partner violence are rarely able to accommodate men [60].

A related and significant issue is sexual assault among gay men in general which tends, due to the shame of the victim as well as bias among some law enforcement officers, to go underreported. Rape crisis programs are often unprepared to deal with male (and especially gay male) victims of sexual assault and rape, and some legal definitions of rape exclude male victims. (See "Evaluation and management of adult and adolescent sexual assault victims".)

On a broader scale, studies have shown that gay men are perhaps frequent victims of violence. Finding a sympathetic place to go can be difficult. One study showed that only a small percentage of violent incidents were reported due to fear that open discussion would lead to further injury and that some victims had been victimized by police [61].

Primary care clinicians in the United States should be aware of the relatively high prevalence of violence and hate crimes against gay men in the community. Although, as with heterosexual intimate partner violence and violence in general, there is little evidence about the benefits of screening or intervention, we believe that it is important to discuss with patients whether they have ever been physically or emotionally assaulted so that appropriate interventions can be deployed.

MAKING CARE ACCESSIBLE — Gay men, like all patients, must be made to feel welcome in order to increase the likelihood that they will be honest with their providers and follow advice for preventive care. Perhaps the most important feature of care is the application of an open and nonjudgmental approach to finding out about each patient, their individual circumstances, concerns, and needs.

The same applies to the general office environment. Educational materials in waiting areas can give subtle signs that a practice may not be sensitive to same-sex issues, particularly if they do not include images of lesbian, gay, bisexual, transgender, and queer (LGBTQ) partners and families.

Some centers are now routinely asking patients for information on sexual orientation and gender identity at the time of registration. Forms asking for this information in language seeming to promote only traditional heteronormative family structures can be off-putting to sexual minorities. Rather than just asking if a patient is married, single, or divorced, there should also be an option to indicate if a patient has a significant other or domestic partner. In countries and states where same-sex marriages are recognized, medical staff should acknowledge these relationships as they would with any heterosexual marriage, and they must recognize the legal status of these relationships for the purposes of hospital visitation [62,63].

In the United States, the Joint Commission and other agencies continue to collect data, looking at ways to improve the care environment for gay men in clinical settings [19,64]. The Joint Commission has implemented policies allowing patient choice of visitors in hospitals, prohibiting discrimination based on sexual orientation, gender identity, and gender expression.

Same-sex couples and families with same-sex parents may look to clinicians for guidance on issues of family commitment, marriage, adoption, parenting, foster parenting, and gestational carrier/surrogate pregnancy in the same ways that two-sex partners and families do. Facilities for families must recognize that increasing numbers of children will now register with two same-sex parents or caregivers. Clinicians must be culturally sensitive and ensure that none of our patients experience psychological barriers to care.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: HIV screening and diagnostic testing" and "Society guideline links: HIV prevention" and "Society guideline links: Health care for lesbian, gay, and other sexual minority populations".)

SUMMARY AND RECOMMENDATIONS

●While much of the care of gay men reflects standard of recommended care of all men, there are unique features regarding both medical and behavioral health of gay men of importance to practicing clinicians. (See "Overview of preventive care in adults".)

●Men who have sex with men (MSM) may not identify as gay; thus, it is important to ask patients about the gender and anatomy of sexual partners rather than sexual orientation, as well as behavior and desire. Providers should routinely ask the following questions to normalize sexually history taking for sexual minorities (see 'Obtaining a history' above):

•"What is your gender?"

•"What sex was recorded on your birth certificate?"

•"Do you have sex with men, women, both men and women, or persons who are non-binary or of another gender?"

•“What type of sex do you have? Insertive anal (top), receptive anal (bottom), or versatile (both)? Oral? Vaginal?”

●Clinicians should perform at least annual HIV and sexually transmitted infection (STI) screening for all sexually active MSM and transgender persons who have sex with men, except those in long-term (>1 year), mutually monogamous, HIV-concordant relationships. In addition to HIV, we screen annually for syphilis, genital chlamydia and gonorrhea, rectal chlamydia and gonorrhea (in those who have had receptive anal intercourse in the prior year), and oropharyngeal gonorrhea (in those who have had receptive oral intercourse in the prior year). More frequent screening every three months is warranted for MSM at particularly high risk for STIs, including those with multiple or anonymous partners. Additionally, MSM should be counseled about safer sex, risk reduction, and the availability of postexposure prophylaxis (PEP) for sporadic exposures to HIV and preexposure prophylaxis (PrEP) for ongoing protection. (See 'Other sexually transmitted infections' above and "Screening for sexually transmitted infections", section on 'Men who have sex with men'.)

●Anogenital human papillomavirus (HPV) infection is highly prevalent among MSM. Men with perianal warts should be carefully evaluated for dysplastic lesions as part of management of those warts. We screen all MSM for squamous intraepithelial lesions (SIL) every two to three years beginning at age 40. Screening for precancerous anal lesions with anal cytology is discussed separately. (See 'Cancer screening' above and "Anal squamous intraepithelial lesions: Epidemiology, clinical presentation, diagnosis, screening, prevention, and treatment", section on 'Our suggested approach'.)

●All MSM should be immunized for hepatitis A and hepatitis B. (See 'Immunizations' above.)

●Primary care providers should modify aspects of their intake forms and office environment to communicate that they provide care that is welcoming to all patients, including gay men. (See 'Making care accessible' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Harvey Makadon, MD, who contributed to an earlier version of this topic review.