This paper examines the association between use of infertility treatment and infant and child health outcomes. Infertility treatment makes conception possible for many couples who otherwise would have been unable to reproduce. Many treatments also increase the chance of having a multiple birth, typically a more risky pregnancy. State insurance mandates compelling insurers to cover or offer to cover infertility treatment induce variation across states over time in access to subsidized infertility treatment. Using birth certificate data, this paper finds the infertility mandates are associated with a statistically significant 10 percent increase in twin births among older mothers. Twin pregnancies are typically more dangerous (and costly) than singleton pregnancies. Thus, even if the only effect of the mandates is to increase twin births, they have likely had a negative effect on infant health. For twins born to older mothers, the mandates are also associated with small but statistically significant negative effects on birth weight, gestation, and the 5-minute Apgar score. Effects for singletons born to older mothers are smaller in magnitude but still negative. Using Census data, the paper finds more mixed evidence about longer term effects of the mandates on child health. The findings for twin birth outcomes suggest that positive effects of investment by older mothers in their pregnancies are outweighed by negative impacts of either the infertility treatments themselves or by the selection into pregnancy of women with reduced fecundity.