Using nationally representative data from the US, this study provides evidence on the relationship between early life conditions and cognition, human capital accumulation, labor market outcomes, and health status in adulthood. We find that poor health at birth and limited parental resources (including low income, lack of health insurance, and unwanted pregnancy) interfere with cognitive development and health capital in childhood, reduce educational attainment, and lead to worse labor market and health outcomes in adulthood. These effects are substantial, and they are robust to the inclusion of sibling fixed effects and an extensive set of controls. The results reveal that low birth weight ages you by 12 years, increases the odds of dropping out of high school by one-third, lowers labor force participation by 5 percentage points, and reduces labor market earnings by roughly 15 percent. Not only are socioeconomic factors determinants of poor birth outcomes, but they also influence the lasting impacts of poor infant health when it occurs. In particular, the negative long-run consequences of low birth weight are larger among children whose parents did not have health insurance. While poor birth outcomes reduce human capital accumulation, this consequence explains only 10% of the total effect of low birth weight on labor market earnings. The study also finds that racial differences in adult health can be explained by a few early life factors: birth weight, parental income, and parental health insurance coverage. Finally, the paper sheds light on the well known strong relationship between education and health outcomes; we find that sibling models that account for time-invariant family factors reduce the effects of education on health substantially, but the remaining effects are large. Taken together, the evidence is consistent with a negative reinforcing intergenerational transmission of disadvantage within the family; parental economic status influences birth outcomes, birth outcomes have long reaching effects on health and economic status in adulthood, which in turn leads to poor birth outcomes for one’s own children.