I can't remember if someone mentioned this before. If they have, sorry for the duplicate. I was looking through the book, Raising Your Child Without Milk by Jane Zukin and came upon the section, Cow's milk is for calves." Here are the 1st 2 paragraphs. Cow's milk comes from female cows. It is the natural food that mother cows provide in order to nurture their calves. In nature, one animal does not suckle another type of animal. Lambs don't nurse from goats, and piglets don't suckle German shepherds. Cow's milk is meant for calves, and it is naturally loaded with the proper nutrients for a bovine baby. Cow's milk contains approximately 21% protein, 45% fat, and 34% carbohydrate or sugar. Human milk contains 8% protein, 55% fat, and 37% carbohydrate. What's more, the types of proteins and fats found in human and cow's milk are quite different in construction and concentration, making each natural only for its own species. This is a difficult concept for many people in our culture to accept, but it is quite elementary, really. A baby animal is biologically programmed to properly digest the milk of a mother of its own species, not that of another species. Therefore, the assertion the cow's milk is natural for human babies is simply and basically incorrect.