Across the vast mine field of the so-called mommy wars, few issues can set off a verbal battle faster than a discussion of breast-feeding and whether a new mother does or doesn't.

The science is clear that infants who are exclusively breast-fed for at least the first six months of life are less likely to develop common childhood ailments such as ear infections and asthma, and are less prone to obesity later in life.

Some studies even suggest that breast-fed babies grow up smarter, possibly because of antibodies they ingest - though the fact that educated, wealthier women who stress early-childhood education are more likely to nurse may have something to do with it.

For women, breast-feeding can help shed postpartum weight by encouraging healthy eating and may cut chances of breast cancer.

Breast-feeding is also a weapon in the fight against poverty, since healthy kids help make healthier, more productive families.

Here in Philadelphia, a new study by the city Health Department shows a woman's likelihood of breast-feeding depends not only on her age, education, and income level, but also the facility in which she receives care.

The study showed low rates of breast-feeding in general among disadvantaged women. But those receiving care at four city hospitals were slightly more likely to try nursing, and stick with it, than women who sought care at eight city health centers. Overall, few inner-city moms kept breast-feeding for more than six months.

The city prides itself as being the first one to legally protect a woman's right to breast-feed in public. Of course, those making that choice must contend with cultural mores and economic factors.

Economically disadvantaged women are more likely to work shift jobs that may not be conducive to breast-feeding, and they may be less likely to eat healthily and avoid alcohol and drugs.

Considering the new study, it's good to see the city increase its role to spread the message about the advantages of breast-feeding. By June, the city's eight health centers will offer additional breast-feeding classes and one-on-one counseling.

A woman may choose not to breast-feed, but it should be an informed choice, and not one made by her pocketbook.