Handedness and its association with gender-related psychological and physiological characteristics

Prenatal exposure to a high level of testosterone is thought to result in sinistrality and increased masculinization in females. This paper seeks to determine whether sinistral females show more masculine characteristics relative to dextral females. Demonstration of such a relationship would support the proposition that testosterone affects laterality. Masculine and feminine personality characteristics, breast size, age at menarche, and regularity of menstruation were measured via a questionnaire administered to 40 dextral and 40 sinistral female university students. Sinistrals were found to score significantly higher on the masculine subscale and lower on the feminine subscale of the Bem Sex Role Inventory relative to their dextral counterparts. No differences were found between the groups for breast size, menstrual regularity, or age at menarche. These results demonstrate that hand preference is associated with gender-related psychological characteristics, but not the physiological characteristics measured. Thus, the possibility that the different sex roles adopted by sinistrals and dextrals is the result of socialisation rather than biological mechanisms, such as testosterone, cannot be ruled out.