Objective Social stigma has had harmful impacts on same-sex families, and its ongoing perpetuation facilitates inequality in policy and practice. Research has consistently identified that people believe that there are negative developmental impacts on children raised by same-sex parent families. These misconceptions about same-sex parenting may be impacting attitudes toward same-sex family rights. Given the connection between marriage and family, the aim was to investigate the effectiveness of an educational intervention that presents factual information about same-sex parenting on attitudes toward sexual minority rights. Method To investigate this proposition, participants (n = 629) responded to an online survey, where they were randomly assigned to one of two conditions in an intervention where they were given either facts about smoking or facts about parenting (i.e., removing misconceptions about same-sex parenting). Participants responded to pre- and post- items to assess the impact of the fact sheet attitudes toward same-sex parenting and same-sex marriage. Results Educating people about the misconceptions of same-sex parenting significantly reduced prejudicial attitudes toward same-sex parenting but not prejudicial attitudes toward same-sex marriage. Post hoc analyses revealed that, after removing strong positive attitudes, a reduction in negative attitudes toward same-sex marriage occurred among those who received information about same-sex parenting. Conclusions The findings demonstrated the impact of educating people about same-sex parenting and illustrated the importance of targeting people who hold prejudicial attitudes, comparative to those who have pre-existing positive attitudes toward same-sex families. The results of this study support the idea that intervening societal attitudes toward same-sex parenting may reduce opposition to same-sex family rights.