N.G.Martin1, K.Kirk1, M.P.Dunne1, J.M.Bailey2
All previous work on the genetics of sexual orientation has used definitions derived from Kinsey that do not necessarily extract the optimum information from the item data available and therefore potentially cloud the question. In an effort to make this less subjective we are using measurement models in a genetic context (see Hewitt, in Neale & Cardon, 1992, chapter 16) to examine the causes of individual differences in responses to 10 items concerning sexual orientation in 4901 individual twins (1890 complete pairs, 1121 singles) aged 18-50 from the Australian Twin Registry who answered an anonymous questionnaire on sexual behaviour and attitudes. Such multivariate methods have the potential to overcome the low power inherent in the analysis of low frequency categorical items.
Address: Queensland Institute of Medical Research, Brisbane 4029, Australia, Phone: + 61 7 3362 0278 Fax: +61 7 3362 0101 Email:, nickM@qimr.edu.au
1Queensland Institute of Medical Research, Brisbane, Australia 2Department of Psychology, Northwestern University, Evanston IL, USA 3Supported by a First Award from NIMH (USA) to JMB and a CARG (Australia) grant to NGM and MPD