This thesis consists of three essays on human capital formation from gestation to adolescence. The first two essays use the Pelotas 1993 Birth Cohort Study, from Pelotas, Brazil. The introductory essay looks at the relationship between household income at birth, late childhood, and late adolescence and variables that reflect human capital at age 18. Our results show that income at birth, during childhood and adolescence affect human capital formation. The estimate points at highest impacts being felt at childhood and birth years. These are consistent with the existence of family borrowing constraints, which are particularly pervasive in earlier years. In the second article we investigate the long-term determinants of human capital, from birth until early adulthood. We use the human skill formation model of (1) to estimate a production function of abilities at birth and at age 11. We follow to measure how these abilities combine to produce human capital outcomes. We find that parental investments have strong effects on all our dimensions of child development and at all ages. Further, we use exogenous shifts in income during pregnancy to show that income shocks can have long lasting effects on child abilities and hence on adult human capital levels. Finally, our results show complementarities between parental investments, parental abilities and child abilities. The third essay investigates Chile Crece Contigo a national-scale early childhood development policy implemented in Chile. The policy intended to improve children s development by enhancing their family environment and parents childcare abilities. We estimate a production function of skills for pre- and post-ChCC cohorts, and find improvements in cognitive and non-cognitive skills for children under two years of age, and mixed results for children over two years of age. The increased abilities are not only associated with higher levels of parental investment but also with an increase in the average marginal product of this variable a.