In every society there have been men who have desired only men, both romantically and sexually. They are known as (male) homosexuals. Just as there are myriad expressions of heterosexuality (from celibacy to prostitution), there are myriad expressions of homosexuality. One of them is known as gay.

The word gay is often used as a synonym for male homosexual behaviour.  Male homosexual behaviour can be attributed to the segregation of sexes and is often observed in boarding schools or prisons. This usage is not entirely correct. The word gay goes beyond mere desire and the sex act itself. It refers to men who embrace a lifestyle based on their sexual orientation. Gays are men who are comfortable with their desire for men and are neither apologetic nor defensive about their sexuality. Gays emphasize the cultural, social and identity aspects of homosexuality; they emphasize these aspects along with the sexual aspect. This distinguishes them from those indulging in homosexual behaviour who may express only the sexual aspect.

Although in recent years the term gay increasingly has come to be used to refer to both same-sex oriented males and females, it generally refers to the former. Indeed, many lesbian organizations reject the term gay as a self-designation, restricting it to males, although this view may be less common among younger lesbian women.

Historically, the term gay stems from the Old Provencal word "gai," meaning high spirited and mirthful. Beginning in the seventeenth century, the term referred to the behavior of a playboy or dashing man about town. By the 19th century, the term had come to also refer to a woman of allegedly loose morals. The term gay did not attain prominence as a self-selected term for openly homosexual individuals until the late 1950s and early 1960s. It became increasingly common in this usage by the 1970s and was established in general usage by gays and non-gay individuals alike by the 1980s.

Gays have historically constituted a stigmatized social category. In most countries a gay can be arrested even if he has sex with a consenting adult male in the privacy of his house. He can legally be denied housing, employment, and public accommodations simply because of his sexual orientation. In response, many gays have created organizations that seek to further their rights, in much the same manner that African Americans and other ethnic minorities did during the 1950s and 1960s and women did during the 1970s and 1980s. The Stonewall Rebellion of 1969 in New York City was a watershed event that qualitatively expanded the political activism that had been growing in the gay community since the late 1950s. This event constituted a spontaneous and militant act of resistance to a police raid on the Stonewall Inn, a popular gay bar in Greenwich Village.

The rebellion spawned a worldwide gay revolution for self-identification, self-esteem and self-reliance amongst gay men everywhere. It also generated greater interest in non-heterosexual lifestyles in academic circles that has led to unravelling of other subcultures based on same-sex desire around the world such as those of 'kotis' in South Asia. Sexologists and sociologists are becoming increasingly aware that society cannot be divided into comparments such as homosexual and heterosexual, gay and lesbian, male and female. There is an entire sexual spectrum out there including bisexuals, transexuals and trangendered people. In fact, sexuality is turning out to be a complex mix of biology, desire, behavior and identity.

In the last few decades the gay men in Europe, U.S. and Australia have established a distinctive subculture that consists of numerous social and cultural institutions, including social and political clubs, community centers, businesses, book stores, publications and other media, cafes, bars, other recreation and vacation institutions, social support and therapy groups, an extensive health education and service structure, and geographically-bounded neighborhoods. It also includes social networks and groups, as well as families or married couples. Because of their stigmatized sexual orientation, gays and lesbians often choose to socialize with each other in a variety of public places, such as bars and cafes.

Whereas the gay subculture in the United States and elsewhere has been in existence for some time, the AIDS epidemic that began in the early 1980s has particularly propelled it into the limelight. In recent years, this subculture has come under increased scrutiny by both the general public and scholars in the social sciences and humanities. Indeed, gay scholars are among the leading figures in an interdisciplinary field now referred to as Gay Studies. This field of research and cultural commentary often takes on a social constructivist perspective, which is sometimes referred to as "queer theory". Intentional use of terms like "queer" or "faggot" within the gay subculture reflects an effort to assert self-acceptance and deny the derision and rejection suffered by homosexuals in mainstream or "straight" society. Gay Pride marches are an expression of the effort among gays to affirm (both to themselves and to non-gays) their right to be gay and their pride and acceptance of their sexual orientation and various subcultural "scenes" (i.e., diverse recreational and lifestyle subgroups).

Many gays desire to have their committed relationships legally recognized as same-sex marriages. Presently, gays do not, for the most part, have the legal right to make medical, legal, and financial decisions on behalf of their partner should the need arise. Furthermore, they may not have access to their partner's employee health insurance or retirement benefits. The onset of the AIDS epidemic has prompted many gays - often in coalition with lesbians and progressive heterosexuals - to agitate for HIV prevention programs and improved health care and treatment options for people living with AIDS, and to oppose discrimination against HIV infected individuals. The gay community played a leading role in pushing for changes in federal funding for HIV/AIDS research and services, and in accelerating access to new therapies of HIV/AIDS.

Although homosexuality has a long history in India, the gay movement is relatively nascent. Until recently, most homosexuals in India did not have many social and cultural avenues to express their sexuality. This is changing now thanks to greater awareness and education. Many men of homosexual orientation are choosing to identity themselves as 'gay' and embracing a lifestyle that resists marriage and other conventions of an otherwise hetersexual society. They remain largely invisible and form networks that shy away from the public glare for fear of social and familial backlash.