Finger length ratio (2D:4D) in left- and right-handed males.
The finger length ratio (2D:4D) is a biomarker for the prenatal levels of testosterone. The prenatal effects of testosterone on the development of brain hemispheres are considered as a key factor in the etiology of left-handedness. We tested whether 2D:4D correlates with the type of handedness in males (18 right-handers and 18 left-handers). Right hand 2D:4D, left hand 2D:4D, average 2D:4D, and the difference between right and left 2D:4D (D(r-l)) were compared. The value of D(r-l) in left-handers was significantly lower than D(r-l) in right-handers. This result can be interpreted as proof that left-handers were subjected to higher levels of testosterone in utero.
Stoyanov
Zlatislav
Z
Department of Physiology and Pathophysiology, Medical University Prof. Paraskev Stoyanov, Varna, Bulgaria. zsd@mu-varna.bg
Marinov
Miroslav
M
Pashalieva
Irina
I
D000328:Adult; D002540:Cerebral Cortex / Q000196:embryology; D005260:Female; D005385:Fingers / Q000033:anatomy & histology* / Q000196:embryology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D013739:Testosterone / Q000502:physiology*; D055815:Young Adult
D013739:Testosterone