Sexual orientation and handedness in men and women: a meta-analysis.
Recent findings suggest that sexual orientation has an early neurodevelopmental basis. Handedness, a behavioral marker of early neurodevelopment, has been associated with sexual orientation in some studies but not in others. The authors conducted a meta-analysis of 20 studies that compared the rates of non-right-handedness in 6,987 homosexual (6,182 men and 805 women) and 16,423 heterosexual (14,808 men and 1,615 women) participants. Homosexual participants had 39% greater odds of being non-right-handed. The corresponding values for homosexual men (20 contrasts) and women (9 contrasts) were 34% and 91%, respectively. The results support the notion that sexual orientation in some men and women has an early neurodevelopmental basis, but the factors responsible for the handedness-sexual orientation association require elucidation. The authors discuss 3 possibilities: cerebral laterality and prenatal exposure to sex hormones, maternal immunological reactions to the fetus, and developmental instability.
Lalumière
M L
ML
Law and Mental Health Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada. martin_lalumiere@camh.net
Blanchard
R
R
Zucker
K J
KJ
D001921:Brain / Q000196:embryology* / Q000276:immunology / Q000502:physiology*; D004292:Dominance, Cerebral / Q000235:genetics* / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000235:genetics; D006716:Homosexuality / Q000235:genetics; D006801:Humans; D008297:Male; D008431:Maternal-Fetal Exchange; D009473:Neuronal Plasticity; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012727:Sex Characteristics