Professor of Psychiatry at the University of Toronto
Pro to the question "Is Sexual Orientation Determined at Birth?"
"The finding that a man's sexual orientation relates to his number of older brothers is based entirely on epidemiological rather than experimental data. The evidence for this relation arises from events in prenatal life rather than experiences in childhood or adolescence is scanty but consistent."
"Quantitative and Theoretical Analyses of the Relation Between Older Brothers and Homosexuality in Men," Journal of Theoretical Biology , 2004
"Sex Ratio of Older Siblings in Heterosexual and Homosexual, Right-Handed and Non-Right-Handed Men," Archives of Sexual Behavior, Dec. 2008
"Deconstructing the Feminine Essence Narrative," Archives of Sexual Behavior, June 2008
"Review and Theory of Handedness, Birth Order, and Homosexuality in Men," Laterality: Asymmetries of Body, Brain and Cognition, Jan. 2008
Cowritten with H.E. Barbaree, C.M. Langton, and D.P. Boer, D. P., "Predicting Recidivism in Sex Offenders Using the SVR-20: The Contribution of Age-At-Release," International Journal of Forensic Mental Health, 2008
Cowritten with J.M. Cantor, M.E. Kuban, T. Blak, P.E. Klassen, and R. Dickey, "Physical Height in Pedophilic and Hebephilic Sexual Offenders," Sexual Abuse: A Journal of Research and Treatment, Dec. 2007
"Older-Sibling and Younger-Sibling Sex Ratios in Frisch and Hviid’s (2006) National Cohort Study of Two Million Danes," Archives of Sexual Behavior, Dec. 2007
Cowritten with J.M. Cantor, A.F. Bogaert, S.M. Breedlove, and L. Ellis, "Interaction of Fraternal Birth Order and Handedness in the Development of Male Homosexuality," Hormones and Behavior, 2006
Cowritten with M.L. Chivers and M.C. Seto, "Gender and Sexual Orientation Differences in Sexual Response to Sexual Activities Versus Gender of Actors in Sexual Films," Journal of Personality and Social Psychology, Dec. 2007
"Quantitative and Theoretical Analyses of the Relation Between Older Brothers and Homosexuality in Men," Journal of Theoretical Biology, 2004
"Fraternal Birth Order and the Maternal Immune Hypothesis of Male Homosexuality," Hormones and Behavior, 2001