Insights into Sex-Based Brain Development in Early Childhood from Newborns' Brains.

New research published in Human Brain Mapping reveals sex differences and developmental changes in the brain’s white matter in healthy, typically developing infants and 5-year-olds. The study found significant detectable differences in multiple regions at the age of 5 years, highlighting sexual dimorphism in brain structure during development. Changes in white matter asymmetry patterns occurred during early childhood, and in 5-year-olds, the pattern already resembled adult-like patterns. The findings suggest that more investigations are required to examine whether these findings associate with developmental cognitive and emotional differences between girls and boys.