Have you ever heard the one about howbreastfeeding用母乳喂养is free? Yeah, it's pretty funny, because it's only free if we don't value women's time and energy. Any mother can tell you how much time and energy it takes toliquify（使）液化her body--toliterally简直 dissolve使（固体）溶解herself-as she feeds this precious littlecannibal同类相食的动物

Milk is whymammals哺乳类动物suck. AtArizona亚利桑那State University, in the ComparativeLactation哺乳、乳汁的分泌、授乳期lab, I decode mother's milk compositon to understand its complexity and how it influences infant development. The most important thing that I've learned is that we do not do enough to support mother's and babies. And when we fail mothers and babies, we fail everyone who loves mothers and babies：the fathers, the partners, the grandparents,  the aunties, the frineds andkin亲属that make our human social networks. It's time that we abandon simple solutions and simple slogans, and grapple with thenuance（意义、声音、颜色、感情方面的）细微差别..

I was very fortunate to runsmack-dab 正好into that nuance very early, during my first interview with a journalist when she asked me,"How long should a mother breasfeed her baby?" And it was that word "should" that brought me up short, because I will never tell a woman what she should do with her body.

Babies survive and thrive because their mother's milk is food, medicine and signal. For young infants, mother's milk is a complete diet that provides all the building blocks for their bodies, that shapes their brain and fuels all of their activity. Mother's milk also feeds themicrobes微生物that arecolonizing（colony的动词）the infant'sintestinal tract 肠道.Mothers aren't just eating for two, they're eating for two to the trillions. Milk provides immunofactors that help fightpathogens致病菌and mother's milk provides hormones that signal to the infant's body.

But in recent decades, we have come to take milk for granted. We stopped seeing something in plain sight. We began to think of milk as standardized, homogenized,pasteurized消毒,packaged, powdered, flavored and formulated. We abandoned the milk of human kindness and turn our priorities elsewhere. At the National Institutes of Health in Washington DC is the National Library of Medicine, which contains 25 million articles- thebrain trust智囊团of life science and biomedical research. We can use keywords to search that database, and when we do that, we discover nearly a million articles aboutpregnancy（n，妊娠）,but far fewer about breast milk and lactation. When wezoom（to move or go somewhere vary fast)in on the number of articles just investigating breast milk, we see that we know much more about coffee, wine and tomatoes.

We know over twice as much abouterectile(able to become still and stand up) dysfunction(the fact of a part of the body not working normally).I'm not saying we shouldn't know about those things-I'm a scientist, I think we should know about everything. But that we know so much less about breast milk---the firstfluid(a liquid)a young mammal is adapted toconsume(to eat or drink ;to use sth, especially fuel, energy or time)-should make us angry. Globally,nine out of 10 women will have at least one child in her lifetime. That means that nearly 130 million babies are born each year. These mothers and babies deserve our best science.

Recent research has shown that milk doesn't just grow the body, itfuels(to supply sth with material that can be burnt to produce heat or power)behavior and shapes neurodevelopment.In 2015, researchers discovered that the mixture of breast milk and babysaliva（the liquid that is produced in your mouth that helps you to swallow food)-specifically, baby saliva-causese a chemical reaction that pruduces hydrogenperoxide(a clear liquid used to kill bacteria and to blean hair)that can killstaph(staphylococcus/a type of bacteria that can cause infections in some parts of the body such as the skin and eyes/葡萄球菌)andsalmonella.

And from humans and other mammal species, we're starting to understand that the biologicalrecipe（a set of instructions that tells you how to cook sth and the ingredients you need for it; a method or an idea that seems likely to have a particular result)of milk can be different when produced for sons or daughters. When we reach fordonor(a person or an organizetion that makes a gift of money,clothes,food,etc. to a charity,etc)milk in theneonatal(connected with a child that has just been born)intensive care unit, or formula on the store shelf, it's nearly one-size-fits-all. We aren't thinking about how sons and daughters may grow at different rates, or different ways, and that milk may be a part of that.

Mothers have gotten the message and the vast majority of mothers intend to breastfeed, but many do not reach their breastfeeding goals.That is not their failure; it's ours, Increasingly common medical conditions likeobesity( a condition in which someone is too fat in a way that is dangerous for their healty),endocrine(connected with glands that put hormones and other products directly into the blood)disorders,C-section(a medical operation in which an opening is cut in a woman's body in order to take out a baby)andpreterm(born or happening ahter a short pregnancy, especially one that is less than 37 weeks.)births all can disrupt the underlying biology of lacatation. And many women do not have knowledgeable clinical support. Twenty-five years ago, the World Health Organization andUNICEF(联合国国际儿童基金）establishedcriteria(the plural form of criterion)for  hospitals to be considered baby friendly-that provide theoptimal(most desirable or favorable)level of support for mother-infant bonding and infant feeding. Today, only one in five babies in the United States is born in a baby-friendly hospital. This is a problem, because mothers cangrapple(to try hard to find a solution to a problem)with many problem in the minutes, hours, days and weeks of lactation. They can have struggles with establishinglatch,with pain, with milk letdown and perceptions of milk supply. These mothers deserve knowledgeable clinical staff that understand these processes. Mothers will call me as they're grapping with these struggles, crying withwobbly(feeling weak and unable to keep balanced)voices."It's not working. This is what I'm supposed to naturally be able to do. Why is it not working?" And just because something is evolutionarily ancient doesn't mean that it's easy or that we're instantly good at it. You know what else is evolutionarily ancient?

Sex. And nobody expects us to start out being good at it. Clinicians best deliver quality equitable care when they have continuing education about how to best support lactation and breastfeeding. And in order to have that continuing education, we need to anchor it tocutting-edge（most advanced stage in the development of sth)research in both life sciences and the social sciences, because we need to recognize that too often historicaltraumas(a serious injury)and implicit biases sit in the space between a new mother and her clinician. The body is political. If our breastfeeding support is notintersectional(交错的）, it's not good enough. And for moms who have to return for work, because countries like the United States do not provide paid parental leave, they can have to go back in as short as just a few days after giving birth.

How do we optimize mother and infant health just by messaging about breast milk to without providing the institutional support thatfacilitates（to make something easy or easier to do)that mother-infant bongding to support breastfeeding? The answer is: we can't. I'm talking to you, legislators, and the voters who elect them. I'm talking to you, job creators and collective bargaining units, and workers, and shareholders. We all have a stake in the public health of our community, and we all have a role to play in achieving it. Breast milk is a part of improving human health. In theNICU（neonatal intensive care unit), when infants are born early or sick or injured, milk or bioactive constituents in milk can be critically important. Environments or ecologies, or communities where there's high risk of infectious disease, breast milk can be incredibly protective. Where there are emrgencies like storms and earthquakes, when theelectricity(a feeling of great emotion, excitement,etc)goes out, when safe water is not available, breast milk can keep babies fed and hydrated. And in the context of  humanitarian crises, like Syrian mothers fleeing war zones, the smallest drops canbuffer(to protect sth against impact, or reduce the shock of an impact)babies from the biggest global challenges.

But understanding breast milk is not just about messaging to mothers and policy makers. It's also about understanding what is important in breast milk so that we can deliver better formulas to moms who cannot or do not breastfeed for whatever reason. We can all do a better job of supporting the diversity of moms raising their babies in a diversity of ways. As women around the world struggle to achieve political, social and economic equality, we must reimaginemotherhood(the state of being a mother)as not the central, core aspect ofwomanhood(the state or condition of being a woman), but(except) one of the many potential facets of what makes women awesome.