barker's main area of expertise is human sexuality, gender and romantic relationships, with a focus on the experiences of people in sexual, gender and relationship communities located outside the mainstream – particularly polyamorous, kink, non-binary and bisexual communities. theoretically their work draws on social constructionism, existentialism and buddhist philosophy. barker, with co-author darren langdridge, has published two edited collections on sadomasochism and on non-monogamy, and a recent book for mental health professionals (co-authored with christina richards). barker founded the journal of "psychology & sexuality" together with langdridge in 2010, and they co-edited it until 2017. barker co-organized the critical sexology series from 2006 to 2018, and birecon (a biennial research conference which takes place prior to the annual bicon event).