其它称呼尚有MOTSS（Member of the Same Sex），该缩语来自1970年代美国的人口调查表格[58]，80年代用于Usenet作为同志新闻组的名称[59]，90年代成为台湾和中国大陆同志社群BBS看板名和论坛名[60][61]。由于社会偏见，产生了对同性恋者的贬称，例如faggot、dyke、queer[62]，兔子、基佬等[63]，都被用来或曾被用来贬损同性恋者。这些贬称，有些可能被重新挪用，而成为具有正面意义的称呼，例如queer本是英文单词的怪异之意，但反而被英美同性恋者重新挪用[64]，最终成为学术研究和电视节目用语，例如酷儿理论（Queer Theory）、同志亦凡人（Queer as Folk）、酷男的异想世界（Queer Eye for the Straight Guy）。但由于仍带贬损意味或有激进颠覆的政治性格等原因，不是所有同志都接受这称呼[65][66]。
由于隐密沟通与社交认同的需要，男同志发展出一套社群用语[70][71]，像是指称性爱角色的1号（攻/Top，插入者）、0号（受/Bottom，被插入者）、0.5号（Both/Versatile（英语：Top, bottom and versatile），插入或被插入都可）；指称交往关系的葛格（哥，偏主动照顾）、底迪（弟，偏被动受照顾），但哥/弟可能会依不同脉络事件互换或不加区分；形容体型打扮的熊（Bear，体态魁武饱满，蓄胡打扮多毛者）、猴（近Twink (男同性恋俚语)，体态精瘦，不蓄胡少毛者）、狼（Wolf，精实黝黑，满脸胡渣有男人味者）等等[32][72][73]。随着时间流逝或地域差异等因素，这些用语有可能舍弃不用、意义产生转变、或为其它词汇所取代[74]。
另外一些证据指出激素与性倾向形成有关，一种说法是出生前的睾固酮浓度影响胎儿脑部结构，在子宫时编译好特定的性倾向、性别认同以及相关的行为、认知和性格特质[113][114]。许多科学家分别考虑了出生顺序、惯用手、头发漩涡、阴茎长短、身高体重关系，无名指/食指长度比例等因素，来研究激素与性倾向的关联（英语：Prenatal hormones and sexual orientation）[115]，Blanchard的研究发现“每多有一个哥哥，该名男子被另外一名男子吸引的可能性就大一些”[116]，研究者认为这可能与母体怀多次男胎产生的免疫反应有关[117][118]，Blanchard也发现发生该现象的男性多数都是右撇子[119]。
出柜源自于英文“Coming out (of the closet)”，指承认、接受和欣赏自身的性倾向或性别认同，并将之与他人分享的历程。与之相对的，隐瞒而不愿表达，称之为“躲在衣柜”或未出柜（Closeted）[131]。一般而言，出柜可分为三个阶段：第一阶段是认识自我，愿意对自己坦承，第二阶段是向他人出柜，将同志身份告知亲友同事，第三阶段是公开生活，将同志身份自由公开地融入生活之中。[132]。近年来，美国人口普查呈现同性伴侣增多的现象，似乎反映了同性恋者被社会接纳认可程度的巨大变化，越来越多同性恋者愿意公开性倾向或公开与同性伴侣的关系[133][134]。
1992年，由Laumann主持的National Health and Social Life Survey利用随机样本抽出美国三千多人调查，报告过去一年内，2.7%男性有过男性性伴侣，1.3%女性有过女性性伴侣，自18岁起，4.9%男性有过男性性伴侣，4.1%女性有过女性性伴侣。自我认同为同性恋（2%）或双性恋（0.8%）男性占2.8%，自我认同为同性恋（0.9%）或双性恋（0.5%）女性占1.4%。该研究还发现认同自身为同性恋或双性恋的男女，通常有良好的教育背景，属于中等或高等社会阶层，集中在城市地区，例如美国最大12个城市，9%男性和3%女性受访者自我认同为同性恋或双性恋[145][154]。
2006-2008年，美国疾病控制与预防中心执行National Survey of Family Growth，依几率抽样13495个15-44岁的样本，报告5.2%的男性，12.5%的女性曾有过同性性行为。自我认同为同性恋（1.8%）或双性恋（2.3%）的男性占4.1%，自我认同为同性恋（1.3%）或双性恋（2.8%）的女性占4.1%[145]。
英国的沃芬敦报告是西方国家对同性性行为除罪化的转折点，很多西方文明国家现在已经对同性恋或同性性行为除罪。一系列的欧洲国家，例如荷兰、德国等已经改变法律或者允许同性婚姻或者在法律上承认长期的同性伴侣关系；一些国家开始允许同性伴侣收养子女。而公开承认是同性恋、双性恋或过去曾经进行过同性性行为的政治家的人数也在上升。这包括了前英国国防秘书附属梅杰（John Major）、波蒂略（Michael Portillo）；公开的同性恋政治家大卫·诺里斯（David Norris（英语：David Norris (politician)））是爱尔兰参议院议员；而现任以及前任爱尔兰总统玛丽·麦阿里斯（Mary McAleese）和玛丽·罗宾逊是爱尔兰同性恋法律改革运动（Campaign for Homosexual Law Reform（英语：Campaign for Homosexual Law Reform））的创始人。这个组织曾在爱尔兰对同性性行为除罪过程中起重要作用。[来源请求]
一项研究回顾表明，女同性恋或男同性恋抚养的孩子的表现较难跟传统性别角色配合，更有可能对同性恋关系持开放态度，此一现象部分是跟遗传因素（美国80％同性伴侣抚养的儿童都是有血缘关系的[169]）和社会化进程（在相对较宽容的学校、邻里和社会环境中长大）有关，但大多数由同性伴侣抚养的孩子会成为异性恋者[170]。夏洛特·帕特森（英语：Charlotte J. Patterson）为美国心理学会进行的2005年回顾发现，现有数据并不能够支持“女同性恋或男同性恋所抚养的孩子有较高机会成为同性恋”的说法[171]。一项研究表明，由同性恋者抚养的孩子更倾向采用非异性恋模式的自我性别认同（其跟性倾向不同），特别是女同性恋者抚养的女儿（男儿较不受代间移转影响）[172]。
二十世纪初，同性恋在西方社会仍普遍受法律压迫；在1952年精神医学会出版第一版精神疾病的诊断列表（DSM-I），同性恋被列为其中。然而该分类系统很快就受到国家心理卫生局（英语：National Institute of Mental Health）赞助研究的强烈检视。该研究以及后续研究都未能发现任何实证资料能支持DSM-I的见解。随着研究资料益发充实，医疗心理卫生专业人员和社会、行为科学家都同意DSM-I对同性恋的见解是来自于社会偏见。1973年，“美国精神医学学会”承认科学研究的证据，将同性恋从精神疾病的诊断列表（DSM-III-R）中去除。[200]。
2012年5月17日，世卫驻美洲的办事处，泛美洲卫生组织，就性向治疗和尝试改变个人性倾向的方法，发表一份用词强烈的英文声明《为一种不存在的疾病治疗（"Cures" for an Illness that Does Not Exist）》。声明强调，同性恋性倾向仍是人类性向的其中一种正常类别，而且对当时人和其亲近的人士都不会构成健康上的伤害，更毋需治疗。世卫在声明中再三指出，改变个人性倾向的方法，不单没有科学证据支持其效果，而且没有医学意义，并会对身体及精神健康甚至生命形成严重的威胁，同时亦是对受影响人士的个人尊严和基本人权的一种侵犯。世卫亦藉发表该声明提醒公众，虽然有少数人士可以能够在表面行为上限制表现出自身的性向，但个人性倾向本身一般都被视为个人整体特征的一部分和不能改变；声明内容同时谴责提供性向治疗的医护人员，是把他们自己与社会偏见看齐，并且反映他们对个人性倾向和性健康议题的绝对无知。世界卫生组织亦提醒各国的医护人员，这么作等同于违反医学道德的第一道原则：“首要的事，不要造成伤害（First, do no harm）。[203]世卫同时透过声明呼吁各地政府，应强烈反对当地的诊所和医院提供性向治疗，并应立法惩处或制裁提供性向治疗的医疗机构。世卫并且建议各地政府应多向公众进行个人性向教育，以消除公众对同性恋者的性倾向歧视。[204]
Definitions Related to Sexual Orientation and Gender Diversity in APA Documents(PDF). 美国心理学协会: 6. 2015 [February 6, 2020]. （原始内容存档(PDF)于2021-01-22）. Sexual orientation refers to the sex of those to whom one is sexually and romantically attracted. [...] [It is] one's enduring sexual attraction to male partners, female partners, or both. Sexual orientation may be heterosexual, samesex (gay or lesbian), or bisexual. [...] A person may be attracted to men, women, both, neither, or to people who are genderqueer, androgynous, or have other gender identities. Individuals may identify as lesbian, gay, heterosexual, bisexual, queer, pansexual, or asexual, among others. [...] Categories of sexual orientation typically have included attraction to members of one's own sex (gay men or lesbians), attraction to members of the other sex (heterosexuals), and attraction to members of both sexes (bisexuals). While these categories continue to be widely used, research has suggested that sexual orientation does not always appear in such definable categories and instead occurs on a continuum [...]. Some people identify as pansexual or queer in terms of their sexual orientation, which means they define their sexual orientation outside of the gender binary of 'male' and 'female' only.
Gloria Kersey-Matusiak. Delivering Culturally Competent Nursing Care. Springer Publishing Company. 2012: 169 [10 February 2016]. ISBN 978-0826193810. （原始内容存档于30 November 2016）. Most health and mental health organizations do not view sexual orientation as a 'choice.'
Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M. Sexual Orientation, Controversy, and Science. Psychological Science in the Public Interest. 2016, 17 (21): 45–101. PMID 27113562. doi:10.1177/1529100616637616. 引用错误：带有name属性“Bailey”的<ref>标签用不同内容定义了多次
What Scientists Know—And Don't Know—About Sexual Orientation. Association for Psychological Science. 2016-04-25 [2017-05-09]. （原始内容存档于2021-02-13）. Various biological factors--including prenatal hormones and specific genetic profiles--are likely to contribute to sexual orientation, though they are not the sole cause. Scientific evidence suggests that biological and non-social environmental factors jointly influence sexual orientation. -- Scientific findings do not support the notion that sexual orientation can be taught or learned through social means. And there is little evidence to suggest that non-heterosexual orientations become more common with increased social tolerance.
* Lisa Diamond. Concepts of Female Sexual Orientation. 2013 [2016-05-11]. （原始内容存档于2021-02-13）. Historically, researchers have presumed that sexual orientation shows fundamental continuity in its expression over time. Although this is generally true for most individuals, some studies have found that a number of individuals － more often women than men － report notable shifts in same-sex attractions, behaviors, and identities over time.
Lisa Diamond - Psychology's Feminist Voices. [2016-05-11]. （原始内容存档于2020-10-22）. Sexual Fluidity attracted substantial media attention. However, the data Diamond collected began to be picked up by anti-gay groups, who espoused that being gay is a choice. Diamond has tried to make her findings clear: she did not find that women "choose" to be gay, or "choose" to become straight, rather, relationships and attractions happen, and there is really no "choice" involved..."This (research) does not mean that sexuality is chosen" - an important point that needs repeating.
Gates, Gary J.; Cooke, Abigail M. United States Census Snapshot: 2010(PDF). Williams Institute, UCLA School of Law. 2011 [2015-04-14]. （原始内容(PDF)存档于2015-06-26）.
Ray Blanchard. Birth order and sibling sex ratio in homosexual versus heterosexual males and females. Annual Review of Sex Research. 1997, 8: 27–67. PMID 10051890.
Ritch C. Savin-Williams. How Many Gays Are There? It Depends(PDF). Contemporary Perspectives on Lesbian, Gay, and Bisexual Identities. 2009: 5–41 [2015-11-12]. doi:10.1007/978-0-387-09556-1_2. （原始内容存档(PDF)于2021-09-19）. These definitional dilemmas are not restricted to one age group or one culture. In the United States, the United Kingdom, and France, exclusive same-sex behavior rarely characterized more than 1% of the adult population. If the definition was broadened to include individuals who had both same- and opposite-sex behavior, who had some degree of same-sex attraction, or at least one of the two, then the proportion of gays expanded considerably– nearly one-fifth of the population of men and women (p. 18). 该数据引自 Sell, R. L., Wells, J. A., & Wypij, D. (1995). The prevalence of homosexual behavior and attraction in the United States, the United Kingdom and France: Results of national population-
based samples. Archives of Sexual Behavior, 24, 235–248.
Laumann, E. O., Gagnon, J. H., Michael, R. T., & Michaels, S. (1994). The social organization of sexuality: Sexual practices in the United States. Chicago: University of Chicago Press.
Pawelski JG, Perrin EC, Foy JM, et al. The effects of marriage, civil union, and domestic partnership laws on the health and well-being of children. Pediatrics. July 2006, 118 (1): 349–64. PMID 16818585. doi:10.1542/peds.2006-1279.
DONALDSON JAMES, SUSAN. Census 2010: One-Quarter of Gay Couples Raising Children. ABC News. 2011-06-23 [2013-07-11]. （原始内容存档于2017-06-30）. Still, more than 80 percent of the children being raised by gay couples are not adopted, according to Gates.
Stacey J, Biblarz TJ. (How) Does the Sexual Orientation of Parents Matter?(PDF). American Sociological Review. 2001, 66 (2): 159–183 [2017-05-27]. doi:10.2307/2657413. （原始内容(PDF)存档于2011-09-28）. This may be partly due to genetic and family socialization processes, but what sociologists refer to as "contextual effects" not yet investigated by psychologists may also be important...even though children of lesbian and gay parents appear to express a significant increase in homoeroticism, the majority of all children nonetheless identify as heterosexual, as most theories across the essentialistt" to "social constructionist" spectrum seem (perhaps too hastily) to expect.
Schumm, W. R. Children of Homosexuals More Apt to Be Homosexuals? A Reply to Morrison and to Cameron Based on an Examination of Multiple Sources of Data. Journal of Biosocial Science. 2010, 42 (6): 721–742. PMID 20642872. doi:10.1017/S0021932010000325.
Maurianne Adams, Lee Anne Bell, Pat Griffin. Teaching for Diversity and Social Justice. Routledge. 2007: 198–199 [2014-12-27]. ISBN 1135928509. （原始内容存档于2015-05-14）. Because of the complicated interplay among gender identity, gender roles, and sexual identity, transgender people are often assumed to be lesbian or gay (See Overview: Sexism, Heterosexism, and Transgender Oppression). ... Because transgender identity challenges a binary conception of sexuality and gender, educators must clarify their own understanding of these concepts. ... Facilitators must be able to help participants understand the connections among sexism, heterosexism, and transgender oppression and the ways in which gender roles are maintained, in part, through homophobia.
Claire M. Renzetti, Jeffrey L. Edleson. Encyclopedia of Interpersonal Violence. SAGE Publications. 2008: 338 [2014-12-27]. ISBN 1452265917. （原始内容存档于2015-05-15）. In a culture of homophobia (an irrational fear of gay, lesbian, bisexual, and transgender [GLBT] people), GLBT people often face a heightened risk of violence specific to their sexual identities.
Kerri Durnell Schuiling, Frances E. Likis. Women's Gynecologic Health. Jones & Bartlett Publishers. 2011: 187–188 [2014-12-27]. ISBN 0763756377. （原始内容存档于2015-05-14）. Homophobia is an individual's irrational fear or hate of homosexual people. This may include bisexual or transgender persons, but sometimes the more distinct terms of biphobia or transphobia, respectively, are used.
Operario D, Burton J, Underhill K, Sevelius J. Men who have sex with transgender women: challenges to category-based HIV prevention. AIDS Behav. January 2008, 12 (1): 18–26. PMID 17705095. doi:10.1007/s10461-007-9303-y.
Catalyst, Sr. Kitty, Staff of San Francisco City Clinic; "Reading This Might Save Your Ass"; 2001, San Francisco HIV Prevention and STD Prevention and Control.
Men Like Us: The GMHC Complete Guide to Gay Men's Sexual, Physical, and Emotional Well-being; Wolfe, Daniel; Gay Men's Health Crisis, Inc; Published by Ballantine Books, 2000; ISBN 0-345-41496-9, 9780345414960.
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