Part of the mission of Breastfeeding USA is to provide evidence-based information. What does that statement mean? What is evidence? In the strictest sense, it is information that is backed by solid, peer-reviewed research based on established scientific principles. For a very long time, there was little strong empirical evidence related to breastfeeding, and most of the existing research was concerned with the components of breastmilk. Thankfully, there is now a growing body of research on many aspects of breastfeeding. Sometimes, the results affirm what we already suspected to be true, and sometimes they are surprising.