ABSTRACT In the present investigation we sought to determine the determining factors for the disapproval of gay marriage in Peru. The study was descriptive. The population consisted of university students, parents of the departments of the Costa region, as well as the abundant national and international doctrine, legislation and jurisprudence. The sample consisted of a group of 350 students, parents of the Freedom, Lima, Piura and Arequipa, between 25 and 30 years of age, who belong or not to the LGBT community. The methods used were the hypothetical-deductive, the historical, dogmatic and systematic law, and the technique was the survey. To test the hypothesis formulated and fulfill the objectives of the investigation, it was used as a source that supports the Thesis, the analysis of the doctrine on Marriage between persons of the same sex and the legal norms applicable in national head...