Early Human Development
Prenatal sex hormones may not exclusively determine effects of hand preference on digit ratios. Genetic determination is an alternative possibility.
To study the likelihood of similar effects of hand preference on digit lengths and digit ratios.
We selected similar numbers of left-handers and right-handers in samples of kindergarten children (N = 101, age range: 3.5–7 years) and adults (N = 189, age range: 17–28 years) and measured digit lengths (excluding the thumb) directly on the palmar hand.
Compared to right-handers, left-handers had longer digits and lower third-to-fourth (3D:4D) digit ratios among children, whereas an opposite pattern of handedness differences occurred among adults.
Effects of hand preference on digit lengths and ratios might be genetically/ontogenetically determined. Also discussed are implications of this set of findings for digit ratio research.
Kumar, Sanjay; Singh, Maharaj; and Voracek, Martin, "Effects of Hand Preference on Digit Lengths and Digit Ratios Among Children and Adults" (2020). Mathematical and Statistical Science Faculty Research and Publications. 56.