A. Plots of primary analysis, Early Learning Composite versus alpha diversity measures, show negative correlations. Covariates: older siblings, paternal ethnicity, sex, maternal education, paternal age, twin status, income B. Secondary analyses with the separate Mullen Scales show a negative association of expressive language with alpha diversity. Covariates: older siblings, paternal ethnicity, sex, maternal education, paternal age, twin status, income.