Homosexuality as a discrete class.

Norris et al. contribute to previous work engaging the question of whether homosexuality has a taxonic structure of categories of individuals with distinct orientation, or whether sexual orientation lies on the sort of continuum suggested by Kinsey and others. Because individuals who report nonheterosexual identities, behavior, and attractions are more likely than heterosexual individuals to meet criteria for a psychiatric disorder their study utilized a National Epidemiologic Survey on Alcohol and Related Conditions. The survey was conducted through personal interviews with one randomly selected adult in each household. Their abstract:

Previous research on the latent structure of sexual orientation has returned conflicting results, with some studies finding a dimensional structure (i.e., ranging quantitatively along a spectrum) and others a taxonic structure (i.e., categories of individuals with distinct orientations). The current study used a sample (N = 33,525) from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). A series of taxometric analyses were conducted using three indicators of sexual orientation: identity, behavior, and attraction. These analyses, performed separately for women and men, revealed low-base-rate same-sex-oriented taxa for men (base rate = 3.0% of those sampled) and women (base rate = 2.7%). Generally, taxon membership conferred an increased risk for psychiatric and substance-use disorders. Although taxa were present for men and women, women demonstrated greater sexual fluidity, such that any level of same-sex sexuality conferred taxon membership for men but not for women.