Research has shown that children who were breastfed score higher on IQ tests and perform better in school, but the reason why remained unclear. Now a new study shows that two parenting skills deserve the credit. Responsiveness to children's emotional cues boosts kids' math and reading skills. Reading to children as early as 9 months of age also significantly improves school readiness. These two skills can give kids an extra 2-3 months' worth of brain development.