Effect estimates and 95% confidence intervals for a standard deviation increase in Shannon Index on BASC-2 scores (SDSixWeeks = 0.54, SDOneYear = 0.55, SDTwoYears = 0.46). Sex-specific estimates derive from models with sex-specific variables for Shannon z-scores. Each outcome was considered in a separate model adjusting for the main effect child sex, gestational age, maternal education, parity, delivery mode, maternal and paternal age at delivery, maternal smoking during pregnancy, early life exclusive breastfeeding, duration of any breastfeeding, and child age at follow up. *indicates an estimate is statistically significant (p < 0.05), brackets highlight where the sex-specific estimates are different from one another (p < 0.1), with the exact p-value of the interaction term in text near the bracket.