Dr Leila Strickland became a mother when she was a few months away from completing her postdoctorate fellowship in cell biology at Stanford University. She spent the first three months of her son’s life “at home on maternity leave, relentlessly struggling to breastfeed. I was having a hard time producing enough milk.” She never expected to find feeding her baby a greater challenge than advanced cytology.

“My mom breastfed me and my sister until we were over two years old. All my life, I’d fully embraced the proposition that breast milk is the best nutrition for a baby, and that this is what I would feed my baby.” Lactation consultants, paediatricians and well-meaning friends told her to just keep trying. “Because I was so unprepared for it, I found it really isolating. I felt like there was something wrong with me.”

Eventually – reluctantly – Strickland decided to bottle-feed her baby with formula. “It was convenient and practical, and made it possible for me to get more sleep, and for my husband to participate. In some ways I was able to be a better mom, and I was a lot happier, but I knew I was making a trade-off. I knew the product my child was getting was optimal for raising cows, that it didn’t have the ideal nutrient composition. It was good enough – but what mom is happy with good enough?”

Eleven years later, Strickland has combined her experiences as both a stressed mother and a cell biologist in a way that could change how we feed our babies for ever: she has worked out how to make human breast milk without the human breast. Her startup, Biomilq, cultures breast cells in a lab – farming them outside the body – and collects the milk they secrete. The company calls it “the mother of all patented technology” and it has caught the eye of Bill Gates, who bought a $3.5m (£2.7m) stake in Biomilq in June. Potentially, it could end the infant formula industry as we know it.

While the science shows breast is best – helping cement the emotional connection between mother and child; providing optimal nutrition, antibodies and bacteria; reducing the risk of obesity and diabetes in adulthood – breastfeeding can be a lottery. Many women find it straightforward and rewarding, but for others it is painful and demoralising. Sometimes babies have tongue-tie and won’t latch on, or the mother has mastitis, or doesn’t produce enough milk for the baby to put on the weight required to satisfy ever-watchful midwives and health visitors. Sometimes the baby is premature, or ill, and needs to be fed through a tube, or the mother is embarrassed about feeding in public, or needs to go back to work. Faced with these challenges, the most determined mothers might express milk with a pump; but pumping can be a time-consuming and often wretched experience.

The other alternative is formula. But, as Strickland says, it is a trade-off. Although their composition has improved, infant formulas are generally made from cow’s milk and therefore have sugars, proteins and fats best suited to calves. Human milk contains hormones, antibodies and friendly bacteria, as well as unique proteins and sugars. Formula also has a substantial carbon footprint; it is made from products that depend on dairy farming, or the cultivation of palm oil or soy. There’s also the shame many mothers feel after they turn to the bottle: women who use formula after struggling with breastfeeding have been shown to experience greater levels of guilt than mothers who chose not to breastfeed from the start.

Founded in January 2020, Biomilq boasts that it is “women-owned, science-led and mother-centred”. Strickland is juggling running the lab with homeschooling her two children through lockdown; in our video call from her house in North Carolina, she is casually dressed in a sweatshirt, and I can hear the sound of plates being knocked off tables in far-off rooms as we speak.

Growing food in a lab is called “cellular agriculture” and Strickland describes her work as if it were a kind of farming. “We start with these amazing cells that line a woman’s mammary gland,” she explains. “Using the same techniques that we’ve used for decades to grow cells outside the body, we’re able to reproduce the behaviour these cells have evolved over millions of years, to produce components in quantities that match the baby’s needs.”

Scientists have long been culturing cells for biomedical research, but it was in 2013, when Maastricht University’s Mark Post served up a lab-grown hamburger to food critics on live TV, that the idea of making food from cells entered the public consciousness. Since then, dozens of startups worldwide have begun to make meat in the same way. No animal has to suffer and there are seemingly endless possibilities, from cruelty-free foie gras to kosher bacon.

Seeing Post’s burger consumed live was “a pivotal moment” for Strickland. It was obvious to her that milk had to be next, though it poses a different technical challenge. “Those guys have to harvest every single cell they grow and turn it into a product,” she says. Her product is the secretion rather than the cell. Just as dairy farmers have different priorities to beef farmers, Strickland’s product demands that she keeps her cells alive and producing for as long as possible, instead of selling them off as soon as they mature.

She started to do homespun experiments with her husband, who has a background in chemistry and engineering. They rented a small lab space and spent about $5,000 (£3,827) on used equipment from eBay, but the experiments were expensive. “We were choosing between feeding cells and feeding our children. We had to choose our children,” Strickland laughs. They used the cheapest source of mammary cells they could find: cow udders bought for $20 (£15) a piece from the bewildered manager of the nearest slaughterhouse, taken to the lab and minced up.

Strickland monitored their growth in different conditions, and when she thought she’d come up with the optimal technique, started experimenting with human breast cells, bought from commercial suppliers who normally provide them for breast cancer research. But she had no budget to test if her cells were actually producing human milk. “For the most part, between 2013 and 2016, I just had a really expensive science hobby that most people in my life thought was extremely weird.”

Burnt out, she gave up her lab in 2016. But no one else seemed to be pursuing her idea and it nagged away. In 2019, Strickland decided “to make one more serious stab at this experiment”. A mutual friend introduced her to Michelle Egger, who would eventually become Biomilq’s CEO. Egger has a background in food science and had been working at the Bill and Melinda Gates Foundation. “I know how to grow cells but I don’t know anything about how to grow a company, so Michelle brought that crucial expertise,” Strickland says.

Egger and Strickland got a commercial lab to run a proof-of-concept experiment, growing cells for a month and collecting samples every day. In February 2020, the results were in: the cells were producing the unique proteins and sugars found in human breast milk. The breakthrough led to the $3.5m investment from Gates, which will allow them to scale up the process, and which has changed Strickland’s life. “I’m really doing my dream,” she says. “I get emotional in our meetings, because it’s really personal for me.”

The breast milk Strickland produces in her lab is different from the milk that comes out of a human breast. It can’t change in response to a baby’s needs, as milk from a breast can (for example, being diluted on hotter days when the baby needs more fluids); it contains no hormones or bacteria from the mother’s biome. Most significantly, it has no antibodies, because these are imported into the milk from the mother’s blood, which disembodied cells can’t do. “That’s a part of breast milk we won’t be able to replicate,” Strickland says, matter-of-factly.

She can afford to be relaxed about this, because Biomilq’s market research suggests babies who drink their product will be getting breastfed anyway, and given Biomilq as a supplement. “Those babies will be getting the antibodies from their own mother, then they will be getting a breast milk with a very similar composition when she’s not able to breastfeed – if she wants to go back to work, say, or sleep through the night.” Their mission statement says their product is for women who “need a little boost”. Their target consumer is someone who is determined to breastfeed, but can’t. Just like Strickland was.

But how liberating will lab-produced breast milk be? It’s easy to imagine a scenario in which employers might be less willing to give women the space and time to breastfeed if a product like this exists. “I do think we want to be careful and conscientious about things like that,” Strickland says. “We certainly wouldn’t want to compromise any woman’s ability to breastfeed.” She pauses. “Any women who are at work and still trying to feed their babies breast milk are spending a good part of their day pumping. That’s what we’d be targeting – the pumping. Saving you from having to do that.”

For Strickland, it’s about addressing the gulf between the expectations put on mothers and the reality. “We want to celebrate breastfeeding, and encourage women to do it. There’s just not a great conversation going on about the challenges,” she says. “Most babies are not exclusively breastfed for six months [as recommended by the World Health Organization] and it’s not because women don’t know or care about the benefits. It’s because modern life really offers women no solution to achieve it.”

***

The pressure not to accept the “good enough” provided by infant formula weighs heavily on mothers who want to breastfeed but are prevented from doing so by biology or circumstance. It’s enough to have fuelled the growth of the underground online breast milk market. The invention of formula should have put an end to the practice of wet nursing; rather, the stigma attached to it has given rise to a new digital wet-nursing economy.

Services such as onlythebreast.com link up breast milk sellers with buyers, leaving it up to buyers to do their own screening. Searches can be narrowed down according to location, the age of the baby the milk has been produced for and whether the seller is following a specific diet: vegan, gluten-free or even paleo. The website advises that frozen expressed milk should be doubled bagged, wrapped in newspaper and put in a cooler with dry ice before being couriered to the recipient. It would set you back around £36 a day to feed the average month-old baby with milk bought here, priced at £1-£1.50 an ounce, not including postage and packaging.

Of course, many women are happy to give their breast milk away for free. There are 15 hospital milk banks in the UK, providing screened, pasteurised donor milk, but it is destined for sick and premature babies in neonatal units. Mothers of healthy babies in search of breast milk often join one of Facebook’s dozens of milk-sharing networks in hope of finding a nearby donor. The Human Milk 4 Human Babies UK Facebook group has more than 27,000 members. A new request for milk is posted every hour or so, often accompanied by photographs of tiny babies, wide-eyed with hunger.

The women posting on these forums have turned to social media out of desperation. One mother, who asked for donor milk to tide her four-week-old over while she “works on topping up” her supply, told me her failure to produce enough milk for him was an “extremely painful” experience. “Everybody agrees that breast milk is a better option than formula.”

Another mother began the search for breast milk a month before her second child was born. It was, she said, “the best decision”. She had “tried everything” to breastfeed her first baby, from renting a hospital-grade breast pump to taking drugs that might help boost lactation, but “nothing worked”. She now drives for at least an hour and a half every other week to collect frozen donor milk for her five-month-old son.

“Human breast milk has nutritional ingredients formula simply doesn’t,” she said. “I think of it as eating quality organic foods versus taking a synthetic supplement. It is the best thing I can give my child.” When I sent a link to the Biomilq site, she replied, “Wow. Finally. Shame [it’s] not available yet as I struggle to keep up with my son’s demand. Will be forced to move on to formula.”

Breast milk has become a symbol of optimal nutrition – and optimal motherhood. But Joan Wolf, associate professor of women’s and gender studies at Texas A&M University and author of Is Breast Best?, says women have been “grossly misled” about the extent of the advantages, because it’s impossible to disentangle the benefits of breast milk from the benefits of having a mother who wants to breastfeed.

“You look at the sociology of breastfeeding, and the beliefs of women who breastfeed: they are determined to do everything they possibly can for their baby,” she says. “They are middle class; they feel they’ve got to keep up with each other.” Wolf argues that we increasingly feel we have a duty to reduce risk to ourselves or our families. “Mothers must reduce any risk to an infant, no matter how small, and no matter the cost to the mother herself. Breast milk gets fetishised because of the risk element – because it’s natural, and because it gives women a feeling of absolute power over their babies.”

The availability of lab-grown milk won’t assuage that desire to minimise all risks to your baby, Wolf says. “One day we will have 15 different breast milks to pick from, each with different qualities. [Mothers] won’t know which to pick. They’ll say, ‘If I take this one the baby will get a gastrointestinal infection, or if I pick this one will they get cancer later.’ And this lab-grown breast milk could be very dangerous, because it could reinforce the idea that it really matters to breastfeed.”

***

Strickland’s work in the US may be groundbreaking, but she is not alone. She has an equally well-funded rival across the Pacific Ocean, backed by investors as diverse as British vegan private equity titan Jeremy Coller and Prince Khaled bin Alwaleed bin Talal Al Saud of Saudi Arabia.

“We are the first biotech company in the world that is using cell-based methods to create milk,” says Fengru Lin, founder and CEO of Singapore’s TurtleTree Labs, with the steely confidence of someone who is sure her company is not only first, but will be the best.

I speak to Lin and TurtleTree’s chief strategist, Max Rye, in a video call to their respective homes in Lin’s native Singapore (Rye moved here from the US when they launched the company). She’s in an emerald blouse, her hair scraped back into a neat ponytail. He is every inch the relaxed American, leaning back on his sofa in a blue polo shirt. Before I even ask my first question, Rye tells me they want mothers to breastfeed. “I always like to say, right at the beginning, we think it’s wonderful. We don’t ever want that to stop. There’s nothing else like it,” he says. “Even though we can make human breast milk as a product, we are still far from the real thing.”

Breast milk was an afterthought for TurtleTree Labs. The company began by culturing cow’s milk without the cow, and can now produce everything from sheep’s and goat’s to camel’s milk, taking stem cells from freshly expressed milk and culturing them, instead of farming mammary cells as Biomilq does.

“It started a few years ago when I was learning to make cheese as a hobby,” Lin explains. “It was difficult to find milk in Asia. There aren’t many cows in Singapore.” She travelled around Indonesia and Thailand, and saw the problems of intensive dairy farming first-hand. “Hormones and antibiotics are being pumped into the cows. As a result, the milk quality really suffers. They are impregnating the cow just to get her milk, again and again, every year. And the amount of methane cows create – 37% of global emissions.”

Lin was working as an account manager at Google at the time, and Rye, a tech executive, came to give a talk on new sustainable technologies. When he mentioned the startups growing meat from cells in a lab, Lin’s mind turned immediately to milk. “Afterwards Fengru came up to me asking about milk,” Rye says. “And I thought, there’s got to be someone working on this. There has to be.” He holds his palms up in disbelief. “But no, nobody was doing this.”

They founded the company together in early 2019, and say it was feedback from dairy companies that prompted them to branch out into breast milk. “The folks who provide milk in the stores are the same people who provide the raw ingredients for infant formula,” Rye says. “They approached us and said, ‘Listen, you’ve got something really interesting: if you can make human milk, you can transform the way infant formula is done.’ We realised, this is where the demand is.” It’s also where the big money is: customers are used to paying a lot more for infant formula than they are for cow’s milk.

Instead of producing and bottling its own breast milk, TurtleTree Labs plans to licence its technology to existing formula companies. Rye won’t tell me the names, only that they are “four of the five biggest in the world”.

There are huge regulatory hurdles to be crossed before lab-grown breast milk can go on sale, but Rye and Lin say getting approval for its individual components will be more straightforward. And they are thinking very broadly about possible consumers: elderly people and cancer patients may one day drink their breast milk – or parts of it.

“Early indications show certain bioactive proteins or complex sugars in human milk could be good for senior care and adult health,” Lin says. Geriatric patients can have similar issues with their digestive system as infants, and early studies have shown certain compounds in breast milk may impede the growth of some cancers. But the benefits are under-researched: there isn’t enough spare human milk to be giving it to adults on a clinically significant scale, and convincing them to try it is a challenge.

As soon as those sugars and proteins get regulatory approval, though, they can be added to existing infant formulas – bringing them closer to breast milk than ever. TurtleTree expect that to happen “as early as next year”.

***

Strickland balks at the idea of working with the formula industry. “There’s already distrust of these companies, the Nestlés and Abbotts of the world,” she says. “We think it’s important to bring this product to market with as much credibility and authenticity as possible, as women and mothers and scientists ourselves. Our customers will appreciate seeing it come from us, rather than them.”

Biomilq’s initial plan is as eye-catching as the product itself: they are going to produce customised breast milk for early adopters, grown from the customer’s own cells. “Moms would go through a fine needle biopsy procedure during their pregnancy,” Strickland explains. “That cell sample would be sent to us so we could start growing it up and producing milk. And then when she’s ready, we can start shipping it to her.”

I wasn’t expecting to hear this: taking cells from pregnant women suggests that Biomilq is not solely for women who are having trouble breastfeeding but is also geared to those who assume they will need help before their baby even arrives. And it’s going to be very expensive, Strickland says: “That would go at a pretty high price point, as a custom service.”

But the initiative is more about demonstrating the potential of the product than the beginning of a business model, she says. “We aim to generate an evangelised group of moms, parents and caregivers, who are excited enough to make that initial level of commitment.”

It is difficult to envisage a way that breast milk grown in a lab can be anything other than an elite product. TurtleTree Labs estimates their milk costs $30 (£23) a litre to produce, and even if that figure comes down dramatically (as they expect it to), the technology involved will always be more expensive than dairy-based formula. While breastfeeding is free, it is rarely compatible with full-time employment. A product like this will give those who can afford it either a nutritional edge, or a professional one.

Isn’t this just going to be for very wealthy women? And won’t it give them even greater advantages than they already enjoy?

“We do not want this to be a product that perpetuates inequalities,” Strickland replies, firmly. “That’s something we think a lot about. Making this widely accessible is very much a part of our long-term plan.” For instance, Biomilq is exploring ways employers might be able to subsidise the product for their staff – although this raises further concerns that employers might expect nursing mothers to return to work earlier. “It’s a bit like a game of whack-a-mole: you push down on one problem and something pops up on the other side,” Strickland concedes.

It may be many years before we can go to the supermarket and buy a bottle of breast milk. But the existence of companies such as TurtleTree Labs and Biomilq could well be a symptom of a problem, rather than a solution. In the wrong circumstances, their products could be used to stop women from breastfeeding in public, or to make formula feeding even more taboo. If women were more supported in breastfeeding, less ashamed of using the “good enough” dairy-based formula and less judged in general, then breast milk grown in a lab might not be necessary.

Strickland thinks once her product is on the market, it will be less easy to judge women for how they feed their babies. “A mom sitting there feeding a bottle of our milk will look the same as a mother with a bottle of formula or her pumped milk. It would be indistinguishable,” she says. Plus lab-grown milk is already provoking much-needed discussions about what we think is “natural”. “If nothing else, I consider Biomilq already a success because we get to participate in these conversations.”

It’s hard to argue with that. But whether lab-grown breast milk changes the conversation for the better depends on who is making it, and who gets to use it. This invention may be Strickland’s baby, but she can’t control what it will grow into.

• Jenny Kleeman is the author of Sex Robots & Vegan Meat: Adventures At The Frontier Of Birth, Food, Sex & Death (Picador).

• This article was corrected on 8 December 2020. We mistakenly said that Leila Strickland’s husband invented the scaffold on which the mammary cells are grown, when in fact they are purchased from another company.