A large body of evidence documents the educational and labor market returns to birth weight, which are reflected in investments in large social safety net programs targeting birth weight and early life health. However, there is no direct evidence on the private valuation of birth weight. In this paper we estimate the willingness to pay (WTP) for birth weight in the US. Using a series of discrete choice experiments, we find that individuals are, on average, willing to pay $1.44 for each additional gram of birth weight. This marginal WTP is particularly high at low birth weights, and turns negative at higher weights. The WTP among parents is higher than among non-parents, and particularly than those who do not plan to have children. Nonetheless, a series of calculations suggest that even the parental WTP for birth weight falls short of the inferred public WTP from large social safety net programs, and is lower than the expected present value of birth weight in the labor market for a US-born child. We present a parsimonious model which is able to explain the different WTP by parental status and the discrepancy between our estimated private valuation and the returns in the labor market: Parents may underestimate the value of birth weight, opening the door for new policy interventions to increase health at birth via informational campaigns.