The author examines the inter-relationship between authenticity, music and gender in relation to a particular contemporary genre, emotional hardcore or emo. Noting how hard rock often defined itself as authentic in contrast to (feminine) pop music, the author argues that it is possible to see the ‘persistence of masculinism’ in wider debates around the performance of (appropriate) fandom. Drawing on a wealth of online data from platforms such as Reddit, Tumblr and Facebook, the author observes that even as male fans of emo distance themselves from hyper-masculine forms of hard (or cock) rock, they also critique the presence of female fans as ‘inauthentic’.