Biomilq and the New Science of Artificial Breast Milk

The biotech industry takes on infant nutrition.
A baby sucks on a bottle attached to an intricate machine of pipes and beakers that form the silhouette of a...
New ventures in the world’s oldest food reflect our era’s enthusiasm for tech-based solutions to perennial human problems.Illustration by Bianca Bagnarelli

Not long ago, I suited up in a white coat and safety goggles and entered a quiet laboratory where an experiment at the frontiers of science and parenthood was under way. A young engineer with a tidy beard escorted me past rows of benches to a large freezer. He opened it to reveal an array of ice-caked steel drawers and, wearing blue Cryo-Gloves (reverse oven mitts, essentially), removed a small bottle from the chill, which measured minus eighty degrees Celsius. At the bottom of the bottle, two hundred and fifty millilitres of liquid had formed a shallow, colorless puck.

I was visiting Biomilq, a startup, founded by Leila Strickland and Michelle Egger, that is working to produce lab-grown breast milk. Biomilq’s headquarters are in North Carolina’s Research Triangle Park, a seven-thousand-acre wedge of pine forests and office complexes between Durham, Chapel Hill, and Raleigh. The bottle creaked as it began to adjust to the room’s warmth, and the engineer hastened to put it back in the freezer.

You could call the bottle’s contents Biomilq, or maybe just milk, or, as the engineer did—indicating a number of smaller bottles also stowed in the freezer—“our best shots to date.” The frozen puck represented a week and a half’s worth of output from a single line of lab-cultured human mammary cells. The company hopes to use these cells and others like them to re-create as closely as possible the process of making human milk. About three years before my visit, in February of 2020, Biomilq announced that it had successfully used cells to produce lactose and casein, a sugar and a protein found in breast milk. “Our opinion as a company—and most of us internally, too—is that breast-feeding, at the breast, has benefits that no one will ever be able to mimic,” Egger, a food scientist turned entrepreneur, told me. “If you can breast-feed—do it. Great. But the reality is, a majority of parents cannot exclusively breast-feed. . . . And that’s not for lack of trying.”

Breast milk is often described as a kind of elixir—“perfect nutrition,” in the words of a 2015 paper in Early Human Development. The health benefits that have been attributed to breast milk include protection against asthma, diabetes, diarrhea, ear infections, eczema, obesity, and sudden infant death syndrome. Some much cited research also credits breast milk with producing smarter children, although this is difficult to substantiate. Tabulating a complete science-backed list of the advantages of breast milk over infant formula can be a challenge. The available data are limited by a lack of structural support for breast-feeding. There are, for example, statistical concerns about comparing parents who can’t undertake the time-intensive process of breast-feeding with those who can. (Studies tend to show that parents who breast-feed are more educated and affluent than parents who don’t, and thus confer other benefits on their children.) Regardless of the precise details of breast milk’s advantages, it remains the widely acknowledged gold standard in infant nutrition; to replicate it in a laboratory would be alchemy. On a neon sign in Biomilq’s office, the words “Making Magic” hang beneath the curve of a decorously abstract lactating breast.

In a conference room labelled “Skim,” I met with Strickland, a mother of two with cropped wavy hair and a soft lisp. On one wall was a series of photographs, by Sophie Harris-Taylor, that depict nursing mothers in various states of domestic weariness and serenity. The photos were among the first things that Egger bought for Biomilq’s workspace—a purchase in keeping with the company’s efforts to build a mom-forward brand. At the heart of those efforts is Strickland’s own experience with breast-feeding. Fourteen years ago, Strickland, then a postdoctoral fellow in cell biology at Stanford, became pregnant. At the time, she lived near Santa Cruz, a beach town in Northern California where a particular goddess-mama vibe around maternity prevailed. “Culturally, there was a lot of promotion of, like, ‘You want to do a natural birth, you don’t want an epidural,’ ” she told me. “You know, ‘Your body is made for this.’ ” To some extent, Strickland embraced that attitude. She certainly planned to breast-feed. But the first weeks of her baby’s life called those expectations into question. “When you find, actually, my body is not making enough milk for my baby—what’s up with that?” she said. “Is my body actually not made for this?”

Strickland began to think of her struggle, a not uncommon one, as a scientific challenge. Then, in 2013, a tissue engineer named Mark Post unveiled a hamburger made from lab-grown beef. Produced at a cost of some three hundred and twenty-five thousand dollars, it tasted, in Post’s words, “reasonably good,” and helped to kick off a period of burgeoning interest among investors in “cellular agriculture,” an area of biotechnology devoted to finding lab-grown alternatives to conventional agricultural products. Startups were using engineered yeast to generate animal proteins, or were culturing animal cells directly. Strickland and her husband, a software developer, were excited about the possibilities. What if there were a way to generate breast milk from cells in a lab? They had moved to North Carolina a few years earlier, and Strickland started to experiment using tissue from a cow udder and secondhand lab equipment. In 2019, a mutual friend introduced Strickland to Egger, a Duke M.B.A. student focussed on social entrepreneurship. (Strickland and her husband are now separated. They are currently litigating disputes over the product and its name, ownership, genesis, and technology. He continues to operate an L.L.C. that they formed together, 108Labs, through which he is pursuing lab-grown milk products on his own.)

Egger has a sign in her office that reads “Wake me when I’m CEO.” She spent her early career at General Mills, where she helped develop such products as Lärabar, Go-Gurt, and low-sugar bulk yogurt for schools. While training as a food scientist, Egger had planned to avoid working on dairy—she has hyperosmia, a heightened sense of smell, and the world of bovine odors was uninviting—but the field’s complexity drew her in. “Dairy research is a little bit of art and science combined,” she told me. “Often we do things not because we know why it works but because we just know that it does.” Egger became Biomilq’s C.E.O.

In 2020, the company received $3.5 million in funding in a round led by Breakthrough Energy Ventures, an investment firm founded by Bill Gates. Biomilq’s early days were shaped by the pandemic. This came with difficulties—the company’s lab manager recalls trading with neighboring startups for gloves and pipettes during supply-chain shortages—but also unexpected benefits. Strickland and Egger would hear “Sesame Street” in the background during calls with investors and know that they were talking to working parents. In 2021, they closed a twenty-one-million-dollar series-A funding round. Then, in 2022, a national formula shortage brought urgent attention to the matter of how babies get fed. It was an opening for a company like Biomilq to promote an alternative—and the opening arrived in an era of enthusiasm for tech-based solutions to the fundamental problems of human life. If fertility and longevity were subject to biotech intervention, why not infant nutrition, too?

The process of making breast milk in a human body begins during pregnancy, when hormonal changes prompt mammary cells to multiply. After delivery, two of the pregnancy hormones—estrogen and progesterone—drop off, while prolactin remains. This spurs the mammary cells to draw carbohydrates, amino acids, and fatty acids from the mother’s bloodstream, and to convert these raw materials into the macronutrients required to feed a baby. In Biomilq’s case, the mammary cells come from milk and breast-tissue samples provided by donors, and the cells multiply in vitro under the care of a team of scientists tasked with keeping them “happy.” The cells are then moved to a hollow-fibre bioreactor—a large tube filled with hundreds of tiny porous tubes that are covered in a layer of the lab-grown cells. As nutrients flow through the small tubes, the cells secrete milk components into the large tube, where they collect.

“Honey, did we order a hit?”
Cartoon by Mick Stevens

Describing the results as “milk components,” not “milk,” is a crucial distinction. Biomilq has demonstrated that its technology can produce many of the macronutrients found in milk, including proteins, complex carbohydrates, and bioactive lipids, but it cannot yet create them in the same ratios and quantities necessary to approximate breast milk. Other elements of breast milk are beyond the scope of the company’s ambition. A mother’s antibodies, for example, are present in her milk, but they aren’t produced by the mammary cells, and, because Biomilq’s product will come from a sterile lab environment, it won’t offer any kind of beneficial gut bacteria.

Then there’s breast milk’s characteristic variability—the way its chemical composition changes over the course of months, days, even a single feed—and its ability to respond (through the mechanism of infant backwash, some suggest) to the nutritional needs of a particular baby. Whatever Biomilq winds up being, it will have to be uniform, and “that is not breast milk,” Strickland said. But she still believes in the power of what’s produced by the human mammary cell. Bovine milk and human milk may have some of the same proteins, but there are “species-specific differences in how those proteins are processed,” she said. “We believe that these components will be more bioactive, more absorbable, and interact better with the gut of the infant.”

Katherine Richeson, who oversees product development at Biomilq, is a cell biologist who conducted research on cancer therapies, including breast-cancer treatment, prior to coming to the company. She was struck by the dearth of research on mammary cells in relation to lactation. “Reading the literature didn’t take that long,” she told me. Bruce German, a chemist and food-science professor at the University of California, Davis, is a leading researcher on the subject of human milk. His work has shown how even indigestible parts of breast milk help to nourish bacteria that improve infants’ gut health. (German has also provided unpaid advice to Biomilq.) He sees the historic lack of academic interest in lactation as the result of prioritizing the concerns of “middle-aged white men” over those of mothers and infants. “There are more papers on wine than there are on milk,” he said.

Biomilq’s methods and equipment are drawn from the world of biopharmaceutical technology, and using them to create a commercially viable food product will require working on a radically different scale. “It’s a two-pronged challenge,” Strickland said. “We want to make orders of magnitude more stuff than what the technology is designed for today, and we want to sell that stuff orders of magnitude cheaper.” When asked about the company’s target consumer, Strickland said that it would be a “worst-case scenario” for her if Biomilq replicated the inequalities that already plague infant feeding. “I won’t consider it a success until it’s fully accessible,” she told me. Egger took a somewhat more pragmatic stance: the company was aiming to one day be priced “at the top end” of infant formula, and would likely be more expensive than that at the beginning. “While accessibility is first and foremost for us, it’s not going to be accessible to every person in the world immediately,” Egger said. For now, the company is making a pitch to customers who are already sold on the value of breast-feeding but are frustrated by its challenges, and who are willing to pay to get their child the next best thing.

The relative value of the next best thing is an open question. “What we care about is not just the best nutritional start in life—we’re looking for the best start in life,” Laurence Grummer-Strawn, who works at the World Health Organization and specializes in infant and early-childhood nutrition, told me. The “best start” offered by breast-feeding encompasses all the things impossible to incorporate into a cell-cultured product—breast milk’s fine-tuned changeability, the parent-child bonding. Without those, “we’re talking about essentially a better formula,” Grummer-Strawn went on. “But frankly, from a nutritional perspective, infant formula is not that bad.” He saw the focus on minute chemical improvements as part of a broader American tendency to prioritize breast milk, the substance, over breast-feeding, the act.

I was thirty-one weeks pregnant when I visited Biomilq’s headquarters, and by then I’d heard friends’ stories of their own labor-intensive efforts to generate human milk. For people embarking on parenthood in 2023, breast-feeding is a recommendation right up there with “Read to your child” and “Don’t smoke.” A large number of American parents start out doing so—83.2 per cent of infants born in 2019 were breast-fed at least briefly, according to the C.D.C. But by six months—the age through which the American Academy of Pediatrics recommends that babies consume only breast milk—24.9 per cent were exclusively breast-fed, and only 55.8 per cent were receiving breast milk at all. “It’s pretty incontrovertible that breast-feeding is optimal nutrition for the baby,” Olena Dobczansky, a nurse and lactation consultant who oversees the breast-feeding program at Manhattan’s Lenox Hill Hospital, told me. It’s just that families leave hospitals like hers and confront a reality that makes the A.A.P. guidelines sound fantastical. “A fourth of American mothers go back to work two weeks after having a baby,” Dobczansky said. At that point postpartum, she noted, “you’re still bleeding.” Paid maternity leave—which, among high-income countries, only the U.S. does not mandate—translates to higher rates of breast-feeding.

Even for parents lucky enough to receive generous paid leave, it takes practice, and often the help of someone with experience, to get a baby properly latched and nursing. The journey from there may involve frightening uncertainty (is the baby getting enough to eat?) and physical discomfort (sore nipples, mastitis), and requires time—breast-feeding is, especially in the beginning, a constant occupation. Pumping necessitates its own choreography. Women I know became fluent in paraphernalia with names ranging from puns (the My Brest Friend nursing pillow) to euphemisms (the Simple Wishes hands-free pumping bra). Some presided over their own frosty vaults: pumping then stockpiling in dedicated freezers, and fretting over power outages during storms. Milk, I was learning, didn’t have to be the result of biotech innovation to seem faintly experimental and very precious.

The story of breast-feeding in America could start with Cotton Mather, who admonished Puritan women to nurse their babies rather than become “one of the careless women, living at ease”—a call to health and hard work which has never quite abated where motherhood is concerned. But who breast-feeds and why has been defined by the same forces that shape life in America more broadly. In the antebellum South, for example, Black women were made to nurse white babies at the expense of their own. Nearly two hundred years later, Black women’s breast-feeding rates lag behind those of other demographic groups, one of many health disparities—along with a stark maternal-mortality rate—that form part of the ongoing legacy of slavery.

“It’s as fraught as abortion,” Jacqueline Wolf, an emeritus historian of medicine at Ohio University and the author of a history of breast-feeding and formula in the U.S., aptly titled “Don’t Kill Your Baby,” told me. “There’s almost nothing that raises more social issues than infant feeding.” Wolf dates the emergence of what became known as “the feeding question” to the eighteen-seventies, when mothers across the country began raising concerns about their milk supply. “The big change that was sparked by urbanization and industrialization was suddenly having to pay attention to a mechanical clock,” she said. Earlier infant-care manuals had advised feeding a baby when he showed signs of hunger. Now medical advice put infants on feeding schedules as rigid as railway timetables. But, as Wolf pointed out, “to build up a milk supply, you need to put the baby to the breast often, especially in the first few months.” The women complaining that they lacked sufficient milk were not, as one theory had it, suffering from the ill effects of too much education during puberty. Rather, they were following advice unwittingly engineered to fail. The contours of the American conversation around breast-feeding were thus established: expert authority counselled one thing, practical reality dictated another, and mothers who found themselves caught in between were often regarded as the source of the problem.

One miracle solution of the late nineteenth century came from a new feature of urban life: milk laboratories, which provided some in the middle class with access to “percentage feeding.” A doctor would study a baby’s stool and arrive at a precise mathematical formula (hence “formula”) for her diet. A milk-laboratory chemist would tweak cow’s milk accordingly. The dominant school of thought in early-twentieth-century child-rearing valued scientific rigor over intuition and tradition; kissing your baby excessively, much less nursing her, came to seem suspect. Even so, some authorities endorsed the medical value of breast-feeding. In 1937, Ladies’ Home Journal published an article headlined “Babies Should Be Breast-fed,” written by Dr. Herman N. Bundesen, the president of the Chicago Board of Health. Bundesen used public-health statistics to make his case: “Out of every ten babies who die in the first year of life, eight are bottle fed—not breast fed.” (Don’t kill your baby!)

Yet imperatives like Bundesen’s rarely translated into meaningful support for women interested in breast-feeding, as Jessica Martucci, a historian of medicine at the University of Pennsylvania and the author of “Back to the Breast,” a study of breast-feeding’s postwar resurgence, has argued. By the nineteen-forties, most mothers were giving birth in hospitals, where orderly routine—babies in nurseries, bottles on schedules—often took priority over the personal attention required to initiate breast-feeding. Sometimes the discouragement was still more direct: into the sixties, some hospitals treated maternity patients with hormonal “dry-up pills.”

Under these circumstances, mothers who wished to breast-feed were often obliged to figure it out for themselves. Niles Polk Rumely Newton, a Columbia-trained psychologist who wrote a popular mid-century child-rearing book, breast-fed her children with help from her mother, but she was troubled by the lack of official guidance. With her obstetrician husband, she devised a series of experiments based on research performed on cows, and she used herself as a test subject. Newton helped to establish the workings of the human “let down” reflex, a hormonal process that prompts the release of milk in response to a baby’s suckling. Basically, a mother had to be able to relax. (A beer could help, the Newtons suggested.) “In the dairy business,” a 1955 Ladies’ Home Journal article on the Newtons noted, “the farmer’s loss can be measured in dollars and cents; perhaps for this reason, far more research has been concentrated on lactation in cows than in humans.”

Commercial infant formula from brands such as Similac and Enfamil took off in the fifties—a modern amenity that sat comfortably alongside Betty Crocker cake mix and Cheez Whiz. (Formula had also made it easier for women to work outside the home.) At the same time, the decade saw the rise of some of breast-feeding’s most influential evangelists. The La Leche League was founded in 1956 by seven Catholic housewives in the Chicago suburbs who wanted to create a forum for breast-feeding mothers to share questions and advice. La Leche occupied a tricky cultural position, at once radical and conservative: on the one hand, it encouraged women to claim control of their bodies and to defy voices of institutional authority; on the other, the intended result of this rebellion was a world in which a mother’s place was unequivocally at home. Still, the appetite for practical help was ravenous. Within twenty years of its first meeting, La Leche had grown to include almost three thousand chapters.

National breast-feeding rates reached their lowest ebb in the early seventies, with only twenty-two per cent of mothers even trying to nurse in 1972. But a shift was already taking place. Feminists sparred with La Leche over its stance on working mothers, yet they, too, sought to empower women facing down the medical establishment. Countercultural currents produced a generation of parents more inclined to feed babies the natural way. In a “Sesame Street” segment from the era, Buffy Sainte-Marie, the singer and Indigenous activist, breast-feeds her baby while Big Bird looks on. It’s “nice and warm and sweet and natural,” Sainte-Marie explains. “And I get to hug him while I do it, see?” It was also an activity with the power to, among other things, épater le bourgeois. “Breast Feeding in Public a Growing Trend,” the Times reported in 1973. As one woman told the paper, “Neither I nor my husband want to go out to dine and be faced with someone’s breast. It’s only happened to us once but let me tell you, it was enough. . . . My husband almost dropped his martini.”

Meanwhile, the alternative to breast-feeding—formula—began to take on a sinister light. An industry that had presented itself as a best friend to mid-century mothers showed a different face in its dealings abroad. New reports linked Nestlé’s aggressive marketing of formula to infant deaths in the Global South, making the case that the company’s product had been pushed on families who lacked the resources (such as clean water) to bottle-feed safely. Instead of a scientifically perfected modern convenience, formula became “The Baby Killer,” in the words of one influential pamphlet. A years-long global boycott of Nestlé ensued. In 1981, the World Health Organization adopted a resolution that aimed to ban the promotion of substitutes for breast milk. The U.S. was the only country in opposition. (Today, Nestlé stresses its compliance with W.H.O. code.)

In the final decades of the twentieth century, the debate over how best to feed babies, once a conflict between mothers and modern science, became a clash among mothers themselves. In one camp was the La Leche League: later editions of the group’s guidebook conceded that certain circumstances might oblige a mother to work, but La Leche never abandoned a fundamental belief that “your baby needs you and you need your baby.” In another camp were mothers who acknowledged other needs, like an identity outside the home or the money required to raise a family. The caricature of nursing zealotry came to look less like a housewife Madonna and more like Maggie Gyllenhaal’s character in the 2009 film “Away We Go,” a smug hippie professor who nurses her toddler and refuses to use a stroller because, as she puts it, “Why would I want to push my baby away from me?” The working mother’s compromise might be formula, or it might be a breast pump—technology that became widely available in the nineties, and was embraced in the U.S. as in no other country.

Yet even as medical and public-health organizations such as the American Academy of Pediatrics rallied behind the value of breast milk and began to propose ambitious breast-feeding goals, women often didn’t have the institutional support to achieve them. Anne Eglash, a clinical professor at the University of Wisconsin, a family physician, and a specialist in breast-feeding, offered the example of a nursing mother suffering from nipple pain who might find herself bouncing between a pediatrician and an obstetrician without getting any answers. The emergence of lactation consultants as a professional field in the eighties helped, but didn’t fully bridge the gap. Government policy itself can undermine breast-feeding: when welfare reform pushed new mothers to return to work sooner, their breast-feeding rates dropped significantly.

In recent years, infant feeding has become yet another consumer choice shaped by advertising. A 2004 campaign by the Department of Health and Human Services and the Ad Council included a commercial in which a pregnant woman rides a mechanical bull. “You wouldn’t take risks before your baby’s born,” the spot declares, before the woman gets tossed from the bull. “Why start after? Breastfeed exclusively for 6 months.” A formula-industry lobbyist sent a letter objecting to the ad campaign before it aired, calling it “appalling” for the government to give mothers “a guilt trip.” The polarized politics of breast-feeding have proved useful to the formula industry and its allies. “Nearly 75% of US parents will turn to formula in the first six months,” a recent ad for the organic-formula startup Bobbie reads. “So why are we ashamed to talk about it?” In 2018, the Trump Administration opposed a U.N. resolution to encourage breast-feeding, in a move seen by many as deference to formula companies. A Health and Human Services spokesman offered the press an alternative rationale, suggesting that the Administration simply hoped to insure that mothers who couldn’t breast-feed were not “stigmatized.” But just because guilt and shame can be used cynically doesn’t mean that they aren’t real. As Martucci, the University of Pennsylvania historian, said, “All the intangible meanings of motherhood have been distilled down into the discrete biological act of breast-feeding your child. And so it carries this huge burden.”

Cartoon by Edward Steed

A product such as Biomilq’s seems tailored to parents whose immediate concern is less about killing their babies than about failing them, and whose interest in breast-feeding is grounded in statistics. This is the cohort that reads Emily Oster, an economist whose data-driven approach to pregnancy and child-rearing has made her an unlikely parenting guru. (“Let’s start by returning from the land of magical breast milk to reality,” one Oster passage analyzing several studies begins.) The relevant ideology here is meritocracy: a belief that you must equip your child for success by excelling according to quantifiable standards. And these standards seem to be rising. The A.A.P. announced last summer that it now supports breast-feeding “until two years or beyond.”

Biomilq hopes to assist parents unable to satisfy this demanding ideal. “We’re fed up with feeling guilty about how we feed our babies,” the company’s Web site proclaims. The emotional core of its pitch is a promise of relief for new parents’ sense of personal inadequacy. “There are two factions in the world: ‘Breast is best’ and ‘Fed is best,’ ” Egger said. “Everyone always wants us to pick a camp.” What Biomilq proposes instead is an escape from dogma through technology, a Third Way politics of breast-feeding.

Biomilq has several competitors in the quest to cultivate human milk’s nutrients in a lab. When I arrived at the headquarters of Helaina, one such company, I was hauling a tote that contained two hundred and ten empty breast-milk-storage bags, extras passed along by a generous co-worker. “You can get a lot of that stuff through insurance,” Laura Katz, Helaina’s founder, said as she ushered me inside. “It’s not that much cheaper, but it feels good.”

Katz gave birth to her first son last July, a month after her company moved into its current space, in Manhattan’s Flatiron district. When we met, the logistics of early parenthood were still fresh in her mind. She told me that she’d recently been working on a database of baby gear that she liked. I thought about the assorted Google spreadsheets that I’d received, detailing the pros and cons of different diaper pails, evidence of a wish that it might be possible, with sufficient research and preparation, to get this whole baby thing right.

Katz, a food scientist, had chosen to breast-feed her son—logging hours with a nursing pillow, pumping during business trips—but her company intends to cater to parents who use formula. Helaina, founded in 2019, genetically engineers strains of yeast so that, when fermented, they produce proteins found in human breast milk. The hope is that these proteins, and the tiny sugars attached to them, will aid immune-system development, in part by feeding the beneficial bacteria in the infant gut. The company’s main lab, a glass terrarium of scientists in white coats, is situated at the center of the office. Nearby, in a room that smelled of bread and Clorox, batches of yeast were churning protein into flasks of frothy fermentation broth, which would be purified and then spray-dried to form a powder. Katz told me that the company was already capable of production at commercial scale. In facilities run by Helaina’s manufacturing partners, spray-drying takes place inside machinery the size of a grain elevator. A sample of the end result—powdered formula in a bin about a foot deep—sat waiting in the lab; Katz would taste-test it that afternoon.

The relative familiarity of Helaina’s “precision fermentation”—which is the same process used to produce insulin and rennet, a set of enzymes for making cheese—has helped put the company several steps ahead of Biomilq. But, to earn government approval, both companies face a daunting process. Becki Holmes, the founder of Foodwit, a consultancy that advises companies on food safety and regulations, explained that products intended to provide complete infant nutrition (that is, formulas) must clear more hurdles than other foods. A new product must, among other things, undergo what are essentially clinical trials, which can involve recruiting hundreds of babies to participate. “All of it is very expensive,” Holmes said. “New innovators are almost discouraged from trying to enter or disrupt Big Formula. You look at what Biomilq is trying to do and it’s a biotech-forward, capital-intense, huge-investment type of innovation work that could still be years away.”

Katz and Egger each told me that they imagine approval will be a two-stage process, with an infant-nutrition product appearing only after less tightly regulated offerings. Helaina hopes to put its protein powder in bars and beverages to be sold by partner brands; Biomilq is considering supplements and toddler food, which it would deliver in 2025. For the company’s infant-nutrition product, “we usually talk about 2028,” Egger said, but these estimates flow as much from business exigency as from scientific reality. “Investors who invest in you in 2020 are excited to see a product come to market in five to seven years, not twenty-five years,” she added.

Infant feeding is a “market that shows enormous stress and desire for change,” Po Bronson, a general partner at the venture-capital firm SOSV and the managing director of its startup incubator, IndieBio, which focusses on life-science companies, told me. Strickland was offered a spot at IndieBio in 2019, and Bronson has remained interested (though not invested) in the field. “I think everybody in it knows it’s going to be really, really hard and come down to lots and lots of details,” he said. Bronson sees the potential for payoff in a growing global middle class. “The demand is great,” he said; the limitation that looms is price. Other entrants in the field include a Singapore-based startup called TurtleTree and an Israeli company that recently changed its name from Biomilk to Wilk. Both are working on animal- and human-milk products.

That the global infant-formula industry beckons would-be disrupters is no surprise—it has been valued at more than thirty billion dollars. But defining success is complicated for a company that considers itself a “social enterprise,” as Biomilq does. Egger told me this meant to her that the company’s “dollars in” had to equal its “impact out”: tilt too far toward prioritizing social good and you’re a nonprofit; tilt too far toward business and “you’re just a standard capitalistic for-profit company.”

The distribution of human breast milk has traditionally taken place at nonprofit milk banks, and recent attempts to introduce commerce into this transaction have stirred controversy. In 2014, a company called Medolac, selling shelf-stable human milk, announced that it would expand its milk-bank program in Black communities in Detroit. The plan was scrapped after backlash from community groups and activists, who called out the company for its low pay in comparison with its pricing and for reinforcing historical injustice. (At the time, the company denied allegations of exploitation.) Biomilq seems keen to avoid any impression of similar obliviousness. Egger told me that the company has encouraged employees to read Andrea Freeman’s “Skimmed,” an account of racial inequities perpetrated by the formula industry. And even as Biomilq describes itself as “women-owned” and “mother-centered,” it also notes that “lactation is not only for cisgender biological mothers.” The company characterizes its work as environmentally friendly, too—reducing reliance on cow’s milk to feed babies could theoretically mitigate the impact of a resource- and emissions-heavy industry. (Breakthrough, the Gates fund, backs companies that seek to address climate change.)

Another question is whether customers will want to buy engineered breast milk. Bo Lönnerdal, an emeritus nutrition professor at U.C. Davis who specializes in breast milk and infant nutrition, told me that in the nineties his lab had produced proteins similar to Helaina’s. (His team used rice instead of yeast.) He remembers that formula companies initially expressed excitement about the possibility—then decided that it was a “non-starter” from a marketing perspective, thanks to growing wariness about G.M.O.s. In recent years, the positive press for breast milk has leaned increasingly on science. But, even so, breast milk remains bound up in the most intimate parts of parenthood, which means that milk from a bioreactor presents a unique dissonance. Biomilq’s efforts at “consumer-empathy education” have involved dozens of hours of interviews with parents, and Egger told me that she’d been surprised at the concerns they raised. They did not seem particularly worried about safety, she said. Rather, they wanted to know how the company would make sure that other parents continued to breast-feed. ♦

An earlier version of this article misstated Katherine Richeson’s role at Biomilq.