Contemporary sex therapy, as a social location within which interventions are made in the field of human sexuality, constitutes a terminal point through which discourses of race, ethnicity, gender and sexuality interface and become meditated. It is also a site in which the particular outcomes of this mediation can be expected to have a significant bearing upon clients who, as social and sexual subjects, carry diverse racialised and ethnicised identities. Though a substantial literature exists pertaining to classical sexology, relatively little is sociologically known about contemporary sex therapy within the UK, and nothing is known of the manner in which discourses of race and ethnicity operate within the field. This exploratory research examines the discourses produced by sex therapists (both in talk and text) regarding the nature and significance of race and ethnicity, and the substantive qualities, significance and effects attributed to these in shaping patterns of human sexuality, sexual dysfunction and sex therapy. The aim is to analyse and account for these discourses as the products of underlying cognitive models of race, ethnicity, gender and sexuality, as these have evolved within the particular social location of sex therapy (as a deposit of a broader racialised and ethnicised social consciousness), and formed the basis of an active utilisation by therapists in the pursuit of `preferred renditions' of sex therapy practice. The thesis also aims to explore sex therapists' accounts of the necessary and sufficient conditions for the achievement of effective, equitable and non-oppressive therapeutic intervention in a context of racial and ethnic diversity. The research supports a rendition of sex therapy as a complex constituency, struggling to make sense of the nature and significance of race and ethnicity as sources of difference, and as dimensions of the social subject. Liberal-humanistic, biological-essentialist and versions of ethnic essentialism compete and coalesce as the primary elements of sex therapists' constructions of race and ethnicity as dimensions of the gendered sexual subject, informing their accounts of the necessary and sufficient conditions for the delivery of appropriate, sensitive and non-oppressive praxis.