同性恋是广泛存在于哺乳动物界的一种现象，人类社会的任何时期都活跃着他们的身影。二十世纪末期，随着同性恋者权利意识的觉醒，在各种同性恋维权组织的推动下，依法保护同性恋者所享有的各项权利这一命题开始被各国立法者所重视，与此同时许多国家和地区以修改法律或重新立法的实际行动来切实支持并保护同性恋者的权利诉求。综观同性恋者所要求的各项权利，其中婚姻权最受争议，这不仅因为该权利挑战了异性恋在社会中的婚姻话语权地位，而且对整个社会传统观念、伦理道德体系、婚姻家庭制度等都产生着颠覆性的作用，因此关于同性婚姻合法化问题的争论近年来愈演愈烈。 在讨论同性婚姻合法化命题时，同性恋者享有婚姻权的法律基础是什么，同性婚姻是否应该被合法化，同性婚姻合法化的实践做法是否适应当前社会现实等一系列问题都极具争议。本文以明确同性婚姻合法化的原因为写作目的，通过文献综述、对比研究、历史研究、文本分析的方法，梳理了同性恋的基本问题，系统介绍了不同历史时期，中西方社会中同性恋群体的生存状况，全面分析了婚姻、婚姻制度以及同性婚姻的理论关系，并最终从必要性和可能性两个方面论证同性婚姻合法化这一命题。

Homosexuality is widespread a phenomenon throughout the mammalian world, at any time in human society are active in their shadow. The late twentieth century, with the consciousness of gay rights in a variety of gay rights organizations, driven by law to protect the rights enjoyed by homosexuals in the proposition that national legislators began to be paying attention and thinking at the same time many countries and regions are also practical action to change the law or new legislation to effectively support and protect the rights of homosexuals aspirations. Looking at the claimed rights of homosexuals are the most controversial of which on the right to marry, this is not only challenging because the rights of a heterosexual marriage in society the right to speak, and its society as a whole concept, the system of ethics, marriage and family system, etc. will have a disruptive role in the debate on the legalization of same-sex marriage issues in recent years intensified. In discussing the legalization of same-sex marriage proposition, homosexuals have the right to marry is the legal basis, whether gay marriage should be legalized, and legalized gay marriage practices to adapt to the current social reality, a series of questions are highly controversial. To clear the legalization of same-sex marriage because the purpose of writing, literature review, comparative study, historical research, text analysis, combing the basic issues of homosexuality and systematic introduction to the different historical periods, in Western society, the gay community living conditions, a comprehensive analysis of the theoretical relationship of marriage, the institution of marriage and same-sex marriage, and eventually legalize same-sex marriage argument from both the necessity and possibility of this proposition.