Attitudes towards same-sex marriage in Portugal: predictors and scale validation

The goal of the present research was to validate a Portuguese version of Pearl and Galupo's (2007) Attitudes toward Same-Sex Marriage Scale (ATSM). Participants were 1,402 heterosexual men and women that completed an on-line questionnaire. The final 15-item scale formed a single factor showing high internal consistency (α = .95). This one factor structure was backed-up by a confirmatory factorial analysis. In a general way, the results indicate a clearly positive attitude toward same-sex marriage (overall mean was 63.79, SD = 12.66, above the scale mid-point, t(1401) = 55.55, p < .001). Furthermore, analysis of the scale's predictors demonstrates how a left-wing orientation (β = .22, p < .001) and the level of denial of deservingness for lesbian/gay discrimination (β = .30, p < .001) prove to be the best predictors of attitudes towards same-sex marriage. On the whole, these results indicate that the Portuguese ATSM version is a reliable instrument for carrying out scientific research and measuring and monitoring public opinion on this subject.