Evaluating the gonads of left-handed children using ultrasonography and comparing the findings with those of right-handed ones.

Unlabelled: Hand use varies according to which brain hemisphere is dominant. Early androgen exposure causes right hemisphere dominance. This study is aimed at comparing the testes and ovary sizes of healthy left-handed girls and boys with those of healthy right-handed children and investigating whether or not lateralization affects the gonads. The ovarian and testicular sizes of healthy left- and right-handed boys and girls who were similar in height, weight, and age were compared by ultrasonography. One hundred and eleven (111) children-including 26 left- and 26 right-handed girls and 31 left- and 28 right-handed boys-were included in this study. The mean age of left-handed girls was 77.2 ± 25.3 months, and the mean age of right-handed girls was 74.4 ± 25.2 months. Right transverse diameter (p = 0.004), right longitudinal diameter (p = 0.009), and right ovarian volume (p = 0.020) were larger in left-handed girls above 8 years of age than in left-handed girls below 8 years of age. However, these values were similar in right-handed girls above and below 8 years of age. In right-handed girls, the transverse diameter was larger in the right ovary than in the left ovary (0.014). Other ovarian values were similar. The mean age of left-handed boys was 85.2 ± 41.3 months, whereas the mean age of right-handed ones was 81 ± 41.2 months. Prepubertal and pubertal right- and left-handed boys had similar mean right and left testicular diameters and volumes (p > 0.05).

Conclusion: Lateralization affected gonad size in girls. In boys, gonads were not affected by lateralization. Cerebral lateralization may affect the hypothalamic-pituitary-gonadal axis in girls.

What Is Known: • Hand use varies according to which cerebral hemisphere is dominant. Males tend to be more left-handed than females. Brain asymmetry can affect the neuroendocrine axis.

What Is New: • Ultrasonographic gonadal dimensions were examined in left-handed and right-handed children. Cerebral lateralization may affect the hypothalamic-pituitary-gonadal axis in girls.