Archives of Sexual Behavior The final publication is available at Springer via http://dx.doi.org/10.1007/s10508-014-0275-5 Original Paper Correspondence: Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, V6T 1Z4, Canada; email: jaimie@jaimieveale.com Evidence Against a Typology: A Taxometric Analysis of the Sexuality of Male-to-Female Transsexuals Jaimie F. Veale Stigma and Resilience Among Vulnerable Youth Centre, School of Nursing, Faculty of Applied Science, University of British Columbia, Vancouver, Canada. Received: 9 July 2007 / Revised: 4 June 2012 / Accepted: 26 December 2013 DOI: 10.1007/s10508-014-0275-5 ABSTRACT: Previous theories and research have suggested there are two distinct types of male-to-female (MF) transsexuals and these types can be distinguished by their sexuality. Using the scales Attraction to Femininity in Males, Core Autogynephilia, Autogynephilic Interpersonal Fanasy, and Attraction to Transgender Fiction as indicator variables, taxometric analysis was applied to an online-recruited sample of 308 MF transsexuals to investigate whether such a distinction is justified. In accordance with previous research findings, MF transsexuals categorized as 'nonandrophilic' scored significantly higher on Core Autogynephilia than did those categorized as 'androphilic'; they also scored significantly higher on Attraction to Femininity in Males and Attraction to Transgender Fiction. Results of one of the taxometric procedures, L-Mode, gave slightly more support for a dimensional, rather than taxonic (two-type), latent structure. Results of the two other taxometric procedures, MAMBAC and MAXCOV, showed greater support for a dimensional latent structure. Although these results require replication with a more representative sample, they show little support for a taxonomy, which contradicts previous theory that has suggested MF transsexuals’ sexuality is typological. KEYWORDS: Autogynephilia, Transsexuals, Sexuality, Gender dysphoria, Taxometric analysis The latent structure of a construct refers to whether it is categorical (variables either one category or the other) or dimensional (occurring on a continuum). Examples of categorical constructs include species, disease entity, job title, chemical element, or genotype. Examples of dimensional constructs include human height, IQ, and yearly income. Categorical constructs have what is referred to as a taxonic latent structure. Each individual category or taxon has objective boundaries to its membership, which are not imposed on a continuum by human social convention. For example, there is an objective boundary between the taxa “cat” and “dog” whereas there is no such boundary between “short” and “tall.” For further explanation of the distinctions between taxonic and dimensional latent structures, see Meehl (1992). Blanchard (1989) proposed that there are two distinct types (taxa) of male-to-female (MF) transsexuals and these distinctions are characterized by their sexuality: “autogynephilic” or “homosexual.” According to Blanchard, autogynephilic MF transsexuals are sexually attracted to females (gynephilic), both sexes (bisexual), or neither sex (analloerotic); they are not unusually feminine in childhood; and prior to transitioning often live outwardly successful lives as males, frequently marrying and having children. These MF transsexuals also experience autogynephilia —a term which Blanchard (1989) used to refer to “a male’s propensity to be sexually aroused by the thought of himself as a female” (p. 616). Homosexual MF transsexuals are exclusively sexually attracted to males (androphilic), do not experience autogynephilia, are highly feminine in their childhood, do not generally have success with attempts to live in the male role, and tend to present for treatment of their gender dysphoria at a younger age. By splitting MF transsexuals into these two groups based on their sexual orientation, Blanchard (1985b, 1988, 1989) and others (Freund, Steiner, & Chan, 1982; Johnson & Hunt, 1990; Nuttbrock, Bockting, Mason et al., 2011; Smith, van Goozen, Kuiper, & Cohen-Kettenis, 2005) have found evidence for the average differences between these groups that Blanchard proposed. However, these differences do not necessarily imply a typology exists. These results could also have been reached if there was a nontaxonic latent structure with a correlation between the sexual orientation of MF transsexuals and these other differences. Although Blanchard (1985a) found some evidence for a taxonic latent structure of the sexuality of MF transsexuals by obtaining cut-off scores for classifying MF transsexuals into two groups using an earlier version of the taxometric procedures described in this article, he did not specifically test whether the sexuality of MF transsexuals was taxonic or dimensional. From studies of physiological measurements of sexual arousal, it has also been observed that the sexual orientation of biological males, including MF transsexuals, is more category-specific than in biological females (Chivers, Rieger, Latty, & Bailey, 2004; Lawrence, Latty, Chivers, & Bailey, 2005). This means that biological males are more likely to respond physiologically to those that they report sexual attractions to. Studies have also shown that androphilic MF transsexuals have a higher number of older brothers than nonandrophilics (Blanchard & Sheridan, 1992; Gómez-Gil et al., 2011; Green, 2000; but see Veale, Clarke, & Lomax, 2010b). While this finding is in accordance