Economist Emily Oster debunks pregnancy and parenting myths using data, revealing that many widely believed restrictions lack scientific evidence while parents waste energy on trivial decisions instead of preparing for the "group project" of raising children. From wine during pregnancy to sleep training, Oster separates correlation from causation, showing parents there are multiple "right" ways to raise kids—and the biggest mistake is obsessing over minor choices rather than thoughtfully planning major ones. Bed rest for pregnancy complications has almost no scientific support and is often harmful, despite being commonly prescribed—a shocking example of how medical advice can contradict actual evidence. Breastfeeding shows only tiny short-term benefits over formula when controlling for socioeconomic factors; most long-term claims about IQ and health are correlation, not causation, fueling unnecessary mother guilt.