Homosexuality is the romantic or sexual attraction or behavior among members of the same sex, situationally or as an enduring disposition. As a sexual orientation, homosexuality is considered to lie within the heterosexual-homosexual continuum of human sexuality, and refers to an individualšs identity based on those attractions and membership in a community of others who share them.

The prevalence of homosexuality is difficult to determine accurately; studies suggest between two and twenty percent of the population exhibit some degree of homosexual sensibility, though in many cultures homosexual relations have been prevalent. Homosexuality is widely encountered in the animal kingdom.

Throughout history, individual aspects of homosexuality have been admired or condemned according to various societies' sexual norms. When praised, those aspects were seen as a way to improve society; when condemned, particular activities were seen as a sin or a disease, and some homosexual behavior was prohibited by law.

Since the middle of the 20th century homosexuality has been gradually delisted as a disease and decriminalized in nearly all developed countries. However, the legal status of homosexual relations varies widely by country and there remain jurisdictions in which certain homosexual behaviors are crimes with severe penalties including death.

Many homosexual people hide their feelings and activities out of fear of disapproval or aggression; they are commonly said to be closeted. Disclosing one's homosexual or bisexual orientation is known as coming out (of the closet). Efforts toward emancipation of homosexuality as it is currently understood began in the 1860s; since the mid-1950s there has been an accelerating trend towards increased visibility, acceptance, and civil rights for lesbian, gay and bisexual people. Nevertheless, heterosexism and homophobia persist, and in particular young people subjected to it are at greater risk of socialization difficulties including suicide. Currently the most common adjectives in use are lesbian for women and gay for men, though some prefer other terms or none at all.

The word homosexual is a Greek and Latin hybrid with the first element derived from Greek homos, 'same' (not related to the Latin homo, 'man', such as in Homo sapiens), thus connoting sexual acts and affections between members of the same sex, including lesbianism.

Gay generally refers to male homosexuality, but may be used in a broader sense to refer to all LGBT people. In the context of sexuality, lesbian refers only to female homosexuality. The word "lesbian" is derived from the name of the Greek island Lesbos, where the poet Sappho wrote largely about her emotional relationships with young women.

The adjective homosexual describes behavior, relationships, people, orientation, etc. The adjectival form literally means "same sex", being a hybrid formed from Greek homo- (a form of homos "same"), and "sexual" from Medieval Latin sexualis (from Classical Latin sexus). Many modern style guides in the U.S. recommend against using homosexual as a noun, instead using gay man or lesbian.

Similarly, some recommend completely avoiding usage of homosexual as it has a negative, clinical history and because the word only refers to one's sexual behavior (as opposed to romantic feelings) and thus it has a negative connotation. Gay and lesbian are the most common alternatives. The first letters are frequently combined to create the initialism LGBT (sometimes written as GLBT), in which B and T refer to bisexual and transgender people.

The first known appearance of homosexual in print is found in an 1869 German pamphlet by the Austrian-born novelist Karl-Maria Kertbeny, published anonymously, arguing against a Prussian anti-sodomy law. In 1879, Gustav Jager used Kertbeny's terms in his book, Discovery of the Soul (1880).

In 1886, Richard von Krafft-Ebing used the terms homosexual and heterosexual in his book Psychopathia Sexualis, probably borrowing them from Jager. Krafft-Ebing's book was so popular among both layman and doctors that the terms "heterosexual" and "homosexual" became the most widely accepted terms for sexual orientation.

As such, the current use of the term has its roots in the broader 19th-century tradition of personality taxonomy. These continue to influence the development of the modern concept of sexual orientation, gaining associations with romantic love and identity in addition to its original, exclusively sexual, meaning.

Although early writers also used the adjective homosexual to refer to any single-sex context (such as an all-girls' school), today the term is used exclusively in reference to sexual attraction, activity, and orientation. The term homosocial is now used to describe single-sex contexts that are not specifically sexual.

There is also a word referring to same-sex love, homophilia. Other terms include men who have sex with men or MSM (used in the medical community when specifically discussing sexual activity), homoerotic (referring to works of art), heteroflexible (referring to a person who identifies as heterosexual, but occasionally engages in same-sex sexual activities), and metrosexual (referring to a non-gay man with stereotypically gay tastes in food, fashion, and design). Pejorative terms in English include queer, faggot, fairy, poof, and homo.

Beginning in the 1990s, some of these have been reclaimed as positive words by gay men and lesbians, as in the usage of queer studies, queer theory, and even the popular American television program Queer Eye for the Straight Guy. The word homo occurs in many other languages without the pejorative connotations it has in English.

As with ethnic slurs and racial slurs, however, the misuse of these terms can still be highly offensive; the range of acceptable use depends on the context and speaker. Conversely, gay, a word originally embraced by homosexual men and women as a positive, affirmative term (as in gay liberation and gay rights), has come into widespread pejorative use among young people.

Homosexuality

Coming out

Religion and Homosexuality

Homophobia

Homosexual behavior in animals

  Cuomo signs NY gay-marriage bill making same-sex marriage legal in NY   MSNBC - June 25, 2011
Catholic bishops claim decision will alter radically and forever humanity's historic understanding of marriage.

  N.Y. becomes sixth and largest state to legalize gay marriage   MSNBC - June 25, 2011
At New York City's Stonewall Inn, the Greenwich Village pub that spawned the gay rights movement on a June night in 1969, Scott Redstone watched New York pass a historic same-sex marriage law with his partner of 29 years, and popped the question.

Same-sex marriage in New York   Wikipedia
A bill permitting same-sex marriage was passed by the New York state legislature on June 24, 2011. The bill was signed by Governor Andrew Cuomo shortly before midnight on the 24th, and the law will take effect 30 days later.

Gay Pride Weekend in NYC (June 25-26, 2011)

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The Stonewall Riots were a series of spontaneous, violent demonstrations against a police raid that took place in the early morning hours of June 28, 1969 at the Stonewall Inn, in the Greenwich Village neighborhood of New York City. They are frequently cited as the first instance in American history when gays and lesbians fought back against a government-sponsored system that persecuted homosexuals, and they have become the defining event that marked the start of the gay rights movement in the United States and around the world.

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June 25, 1978
The rainbow flag representing gay pride first flew in the San Francisco Gay Freedom Day Parade.   Wikipedia

Census 2010: One-Quarter of Gay Couples Raising Children   ABC - June 23, 2011
An estimated one-quarter of all same-sex households are raising children, according to U.S. Census data, providing one of the first portraits of gay American families. For the first time ever, the census counts same-sex couples and their children, and as data trickles out state by state, more gay families are being tallied in the South.

Is Homosexuality Based on a Brain Chemical?   Live Science - March 26, 2011
Serotonin is known to regulate sexual behaviors, such as erection, ejaculation and orgasm, in both mice and men. The compound generally dampens sexual activity; for instance, antidepressants that increase the amount of serotonin in the brain sometimes decrease sex drive. Neuroscientist Yi Rao of Peking University and the National Institute of Biological Sciences in Beijing, and his collaborators have now shown that serotonin also underlies a male's decision to woo a female or another male. Rao and his team genetically engineered male mice to lack either serotonin-producing neurons or a protein that is crucial for making serotonin in the brain.

Both types of altered mouse couldn't make serotonin. Unlike typical males, mice deficient in the neurotransmitter showed no inclination to mount sexually receptive females more than males, nor did they prefer to smell females' genital odors or bedding. Instead, they climbed onto males and serenaded them with ultrasonic love songs more frequently than normal. Males emit these vocalizations when they encounter females to make them more receptive to mating.

Late-blooming lesbians: women can switch sexualities as they mature   Telegraph.co.uk - July 12, 2010
Women are embracing lesbianism in their thirties, according to research indicating that shifts in sexual orientation may be more widespread than previously thought.

How Gay Uncles Pass Down Genes   Live Science - February 11, 2010
A new study found that homosexual men may be predisposed to nurture their nieces and nephews as a way of helping to ensure their own genes get passed down to the next generation. Research has confirmed that male homosexuality is at least partly hereditary - it tends to cluster in families, and identical twin brothers of gay men are more likely to be gay than fraternal twin brothers, who do not share identical DNA. But scientists have been puzzled about how these genes are perpetuated, since homosexual males are less likely to reproduce than straight males. Basically, why haven't gay people gone extinct?

Children Raised by Lesbians Do Just Fine, Studies Show   Live Science - February 8, 2010
The finding, which comes from a review of essentially all studies on the topic of same-sex parents and the health of their children, helps to tease out politics and science on this highly divisive issue. In general, kids in both heterosexual and lesbian households had similar levels of academic achievement, number of friends and overall well-being. Whether or not kids from homosexual households are more likely to have a non-heterosexual orientation is still unknown. But if there is a genetic component to sexual orientation, it would make sense that kids born to a lesbian mom, say, would be more likely than other kids to be homosexual, scientists say.