同性恋连同双性恋和异性恋构成了性取向连续光谱的三区带。科学家尚未明确性取向成因，但普遍认为它由基因、激素和环境影响交互作用而决定，并认定性取向不可选择。他们赞成基于生物学的理论，指出性取向涉及基因、早期子宫环境、或两者兼有，或基因和社会因素共同作用。但未有确切证据指出子女教养、早期童年经历对性倾向有影响。虽然有些人认为同性性行为反自然，但科学证据已表明同性恋是人类性倾向的正常和自然形式之一，并且其本身并不产生任何负面心理伤害。同时目前尚未有充足证据证明运用心理干预可以改变性取向。

对同性恋者常用的称呼为同志，男性为男同志（Gay），女性为女同志（Lesbian），gay一词有时也通称所有男女同性恋者。认同自己是同志身份的人数和有过同性性行为经历的人数，皆由种种原因难以为研究者确切估计，其中之一是很多同志由于恐同心理或者异性恋者的歧视没有公开自己的性取向。在自然界，人们也观察到并记录过很多动物间的同性性行为。

Homosexuality (from Ancient Greek ὁμός,meaning "same", and Latin sexus, meaning "sex") is romanticattraction, sexual attraction or sexual behavior between members of the samesex or gender. As a sexual orientation, homosexuality is "an enduringpattern of emotional, romantic, and/or sexual attractions" to people ofthe same sex. It "also refers to a person's sense of identity based onthose attractions, related behaviors, and membership in a community of otherswho share those attractions."[1][2]
Along with bisexuality and heterosexuality,homosexuality is one of the three main categories of sexual orientation withinthe heterosexual–homosexual continuum.[1] Scientists do not know the exactcause of sexual orientation, but they believe that it is caused by a complexinterplay of genetic, hormonal, and environmental influences,[3][4][5] and donot view it as a choice.[3][4][6] They favor biologically-based theories,[3]which point to genetic factors, the early uterine environment, both, or theinclusion of genetic and social factors.[7][8] There is no substantive evidencewhich suggests parenting or early childhood experiences play a role when itcomes to sexual orientation.[7] While some people believe that homosexualactivity is unnatural,[9] scientific research has shown that homosexuality is anormal and natural variation in human sexuality and is not in and of itself asource of negative psychological effects.[1][10] There is insufficient evidenceto support the use of psychological interventions to change sexualorientation.[11]
The most common terms for homosexual peopleare lesbian for females and gay for males, though gay is also used to refergenerally to both homosexual males and females. The number of people whoidentify as gay or lesbian and the proportion of people who have same-sexsexual experiences are difficult for researchers to estimate reliably for avariety of reasons, including many gay or lesbian people not openly identifyingas such due to homophobia and heterosexist discrimination.[12] Homosexualbehavior has also been documented and is observed in many non-human animalspecies.[13][14][15][16][17]
Many gay and lesbian people are incommitted same-sex relationships, though only recently have census forms andpolitical conditions facilitated their visibility and enumeration.[18] Theserelationships are equivalent to heterosexual relationships in essentialpsychological respects.[2] Homosexual relationships and acts have been admired,as well as condemned, throughout recorded history, depending on the form theytook and the culture in which they occurred.[19] Since the end of the 19thcentury, there has been a global movement towards increased visibility,recognition, and legal rights for homosexual people, including the rights tomarriage and civil unions, adoption and parenting, employment, militaryservice, equal access to health care, and the introduction of anti-bullyinglegislation to protect gay minors.

发帖：勇敢爱阿K