While American women have, and always should have, the right to choose how to feed their infants, many Americans simply do not understand the difference between breast milk and infant formula.  Many people feel that formula is "as good as" or "close to" breast milk. 

An infant can surely survive and grow and develop while consuming manufactured infant formula, but formula will never be a true substitute for mother's milk.

Because human milk is so superior to infant formula and so beneficial to human babies, and because the health and intelligence of future generations are important to our society, it is crucial that our society support (and further, encourage) breastfeeding. 

Breast milk/Breastfeeding:

• Has low protein content/high carbohydrate content which matches the needs of a slow-maturing mammal with an advanced brain (human)
• Changes to match the specific nutritional needs of a specific human baby, based on his/her environment and growth (even the fat content adjusts based on the baby's eating pattern)
• Changes during a feeding; provides thin, lower calorie fore milk for thirst quenching at the beginning of a feeding and provides thick, high fat hind milk at the end of a feeding to provide needed calories and give baby a satiated feeling
• Defends against disease; contains secretory antibodies to protect against specific pathogens, based on what diseases mother and baby are exposed to
• Contains lactoferrin, which in addition to providing iron, also has antibacterial and antiviral properties
• Provides immunological protection against many chronic diseases; lessens risk of diabetes, celiac disease, Crohn's disease, childhood cancer, asthma, and many other diseases
• Reduces the risk of SIDS (Sudden Infant Death Syndrome)
• Contains Cholecystokinine, a gastrointestinal hormone, which signals feelings of sedation, satiety, and well-being in the infant and can also help the infant stay asleep
• Optimizes cognitive function and vision development through long-chain polyunsaturated fatty acids
• Directly contributes to brain growth; DHA, an Omega-3 fatty acid found in breast milk provides the right substances for manufacturing myelin (insulation for nerve fibers)
• Reduces the risk of breast cancer for the breastfeeding mother
• Contains high levels of cholesterol infants need for brain building and manufacturing of hormones and vitamin D
• Promotes brain growth through high levels of lactose, which breaks down into glucose and galactose (galactose being a valuable nutrient for brain tissue development)
• Protects against future obesity due to the healthier fats present in breast milk, the fore milk/hind milk composition of milk (a thirsty baby drinks lower calorie hind milk and is satisfied; a hungry baby consumes both and get the calories he needs), the way human milk adapts in fat content (younger babies need more calories/lb, while older babies need less, and mother's milk adjusts to this), and slower eating and satiety aspects of breastfeeding
• Reduces risk of ear infections and hearing problems; babies can be allergic to the cow's milk proteins in formula which can cause fluid to build up behind the middle ear, dampening vibrations and decreasing hearing as well as providing a breeding ground for ear infections
• Promotes good jaw alignment and reduces the need for orthodontic; sucking at the breast requires more complex motions of the facial muscles and tongue that lead to better jaw alignment (and more room for teeth) due to improved development of the facial muscles, jaw bones, and palate
• Aids in better breathing, due to the development of a larger nasal space as a result of the unique sucking required for breastfeeding
• Promotes intestinal health due to the presence of soft, easy-to-digest whey protein
• Reduces risk of gastroesophageal reflux because breast milk is easiest for baby to digest
• Helps develop the intestinal lining; immunoglobulin A, a special protein found in breast milk, serves as a protective sealant in an infants immature digestive tract and epidermal growth factor, a special substance also found in breast milk promotes growth of the infant's cell lining (as well as other surface cells)
• Maintains bowel health by promoting healthful bacteria (such as bifidus, growth of which is encouraged by the high levels of lactose in human milk) and inhibiting growth of harmful bacteria
• Promotes immunity; breast milk is a living substance (a single drop of breast milk contains around 1 million white blood cells and these macrophages "gobble up" the germs) 
• Lowers incidence of eczema through its immunity-boosting properties and protection from allergies

Breast milk/breastfeeding does this and so much more.  And I didn't really touch on all the actual health benefits for the mother or the benefits to the environment.  Formula, no matter how adequate it may be, can never replicate the contents, nor the benefits, of human milk. 

UNICEF and WHO both recommend that babies breastfeed until at least 2 years of age. 

I am absolutely, completely passionate about the importance of breastfeeding and of insuring the rights of breastfeeding mothers.  The overwhelming health benefits of breastfeeding far outweigh the fleeting and typically avoidable discomfort another person may feel if he or she happens to see a woman nourishing her baby in the mall or at a restaurant. 

Breast milk is the perfect food for human babies.  We should be CONGRATULATING women for making such a healthy, positive choice instead of looking down our noses at them or shoving them off into filthy bathrooms to feed their babies.

Sources:  La Leche League International and The Breastfeeding Book (Martha Sears, RN and William Sears, MD