Sex differences in brain-behavior relationships in the first two years of life.

Multiple linear regression was used to test the interaction between sex and early childhood resting-state functional connectivity on future behavioral scoresSix age-specific, intra-hemispheric functional connections displayed sex differencesMost connections exist within prefrontal regions (with one connection in the temporal pole)Functional connections are specific to brain-behavior relationships and not in brain connectivity aloneSex differences in brain-behavior relationships are robust at smaller sample sizes.