There are many parenting practices that are desirable but not absolutely necessary, and parenting would likely be a joyless business if they were all legally enforced. Helping children with their homework, persuading them to participate in sports, encouraging them to keep and care for pets, and facilitating relationships between children and their grandparents are all, plausibly, good but not essential for children. Yet it is far from obvious that they ought to be legally enforced. Such legal intervention may bring benefits for children, but these must be weighed against the harms arising from the restriction on parents’ freedom to raise their families as they wish and the familial disruptions likely to occur when parents are punished for non-compliance. Even without legislation, however, parents can be persuaded to adopt these desirable practices, via public health campaigns, the media, cultural changes, and so on. In such cases—and perhaps also in the case of breastfeeding—the law is not the best tool for safeguarding children’s well-being.The "perhaps" in the last sentence hints at a lingering doubt. Biologically, breastfeeding is continuous with pregnancy and has clear and certain health benefits. If you have to complete a pregnancy by law, is it so far-fetched to say you have to complete pregnancy and its biological last chapter--lactation? As a matter of pure ethics, it doesn't seem outrageous. But then, there's nothing really "pure" about ethics. "Get your hands off my body," women are going to think, reaching back into the language of the pro-choice movement. Mandatory lactation calls to mind mandatory impregnation, and Margaret Atwood's book The Handmaid's Tale. A law that triggered that sort of anger and offense simply couldn't do anybody any good. I suspect that if we had lactation laws in the US, women would actually rebel by breastfeeding less.
So: there should be no legal requirement to breastfeed. It's just an ethical matter: breastfeeding has important health benefits. Just as women should put their kids in car seats and buckle their seatbelts and give them check-ups and vaccinations, they should give them the best start in life by breastfeeding them. Right? In fact, "mothers should breastfeed" seems to trigger that "get your hands off my body" reaction in some women, even if the "should" is simply ethical, and not legal. That's very puzzling, but a topic for another day.