At birth, a babies brain weighs 12 ounces. It then grows rapidly through infancy and the preschool years, just like everything else in the body. Along with the size of the brain increasing rapidly, babies are able to learn rapidly.
When do babies start teething? Find out when you'll see baby's first tooth—and when you can expect all the other teeth too—in our baby teething chart. * You can get additional details at the image link.