What we know: Studies remain inconclusive. For now, the AAP considers soy safe for full-term infants.
Who should drink it: Few babies need to. There's a lactose-free cow's milk formula for infants with lactose intolerance, and hydrolyzed or amino acid-based kinds for allergic kids. That makes soy necessary only if you don't want your child to have animal protein for religious or ethical reasons, or if your baby has galactosemia, a rare hereditary condition.