With Lab-Grown Chicken Nuggets, Dumplings, and Burgers, Futuristic Foods Aim to Seem Familiar
Sandhya Sriram is at the forefront of the expanding lab-grown meat industry in more ways than one.
"[Lab-grown meat] is kind of a brave new world for a lot of people, and food isn't something people like being brave about."
She's the CEO and co-founder of one of fewer than 30 companies that is even in this game in the first place. Her Singapore-based company, Shiok Meats, is the only one to pop up in Southeast Asia. And it's the only company in the world that's attempting to grow crustaceans in a lab, starting with shrimp. This spring, the company debuted a prototype of its shrimp, and completed a seed funding round of $4.6 million.
Yet despite all of these wins, Sriram's own mother won't try the company's shrimp. She's a staunch, lifelong vegetarian, adhering to a strict definition of what that means.
"[Lab-grown meat] is kind of a brave new world for a lot of people, and food isn't something people like being brave about. It's really a rather hard-wired thing," says Kate Krueger, the research director at New Harvest, a non-profit accelerator for cellular agriculture (the umbrella field that studies how to grow animal products in the lab, including meat, dairy, and eggs).
It's so hard-wired, in fact, that trends in food inform our species' origin story. In 2017, a group of paleoanthropologists caused an upset when they unearthed fossils in present day Morocco showing that our earliest human ancestors lived much further north and 100,000 years earlier than expected -- the remains date back 300,000 years. But the excavation not only included bones and tools, it also painted a clear picture of the prevailing menu at the time: The oldest humans were apparently chomping on tons of gazelle, as well as wildebeest and zebra when they could find them, plus the occasional seasonal ostrich egg.
These were people with a diet shaped by available resources, but also by the ability to cook in the first place. In his book Catching Fire: How Cooking Made Us Human, Harvard primatologist Richard Wrangam writes that the very thing that allowed for the evolution of Homo sapiens was the ability to transform raw ingredients into edible nutrients through cooking.
Today, our behavior and feelings around food are the product of local climate, crops, animal populations, and tools, but also religion, tradition, and superstition. So what happens when you add science to the mix? Turns out, we still trend toward the familiar. The innovations in lab-grown meat that are picking up the most steam are foods like burgers, not meat chips, and salmon, not salmon-cod-tilapia hybrids. It's not for lack of imagination, it's because the industry's practitioners know that a lifetime of food memories is a hard thing to contend with. So far, the nascent lab-grown meat industry is not so much disrupting as being shaped by the oldest culture we have.
Not a single piece of lab-grown meat is commercially available to consumers yet, and already so much ink has been spilled debating if it's really meat, if it's kosher, if it's vegetarian, if it's ethical, if it's sustainable. But whether or not the industry succeeds and sticks around is almost moot -- watching these conversations and innovations unfold serves as a mirror reflecting back who we are, what concerns us, and what we aspire to.
The More Things Change, the More They Stay the Same
The building blocks for making lab-grown meat right now are remarkably similar, no matter what type of animal protein a company is aiming to produce.
First, a small biopsy, about the size of a sesame seed, is taken from a single animal. Then, the muscle cells are isolated and added to a nutrient-dense culture in a bioreactor -- the same tool used to make beer -- where the cells can multiply, grow, and form muscle tissue. This tissue can then be mixed with additives like nutrients, seasonings, binders, and sometimes colors to form a food product. Whether a company is attempting to make chicken, fish, beef, shrimp, or any other animal protein in a lab, the basic steps remain similar. Cells from various animals do behave differently, though, and each company has its own proprietary techniques and tools. Some, for example, use fetal calf serum as their cell culture, while others, aiming for a more vegan approach, eschew it.
"New gadgets feel safest when they remind us of other objects that we already know."
According to Mark Post, who made the first lab-grown hamburger at Maastricht University in the Netherlands in 2013, the cells of just one cow can give way to 175 million four-ounce burgers. By today's available burger-making methods, you'd need to slaughter 440,000 cows for the same result. The projected difference in the purely material efficiency between the two systems is staggering. The environmental impact is hard to predict, though. Some companies claim that their lab-grown meat requires 99 percent less land and 96 percent less water than traditional farming methods -- and that rearing fewer cows, specifically, would reduce methane emissions -- but the energy cost of running a lab-grown-meat production facility at an industrial scale, especially as compared to small-scale, pasture-raised farming, could be problematic. It's difficult to truly measure any of this in a burgeoning industry.
At this point, growing something like an intact shrimp tail or a marbled steak in a lab is still a Holy Grail. It would require reproducing the complex musculo-skeletal and vascular structure of meat, not just the cellular basis, and no one's successfully done it yet. Until then, many companies working on lab-grown meat are perfecting mince. Each new company's demo of a prototype food feels distinctly regional, though: At the Disruption in Food and Sustainability Summit in March, Shiok (which is pronounced "shook," and is Singaporean slang for "very tasty and delicious") first shared a prototype of its shrimp as an ingredient in siu-mai, a dumpling of Chinese origin and a fixture at dim sum. JUST, a company based in the U.S., produced a demo chicken nugget.
As Jean Anthelme Brillat-Savarin, the 17th century founder of the gastronomic essay, famously said, "Show me what you eat, and I'll tell you who you are."
For many of these companies, the baseline animal protein they are trying to innovate also feels tied to place and culture: When meat comes from a bioreactor, not a farm, the world's largest exporter of seafood could be a landlocked region, and beef could be "reared" in a bayou, yet the handful of lab-grown fish companies, like Finless Foods and BlueNalu, hug the American coasts; VOW, based in Australia, started making lab-grown kangaroo meat in August; and of course the world's first lab-grown shrimp is in Singapore.
"In the U.S., shrimps are either seen in shrimp cocktail, shrimp sushi, and so on, but [in Singapore] we have everything from shrimp paste to shrimp oil," Sriram says. "It's used in noodles and rice, as flavoring in cup noodles, and in biscuits and crackers as well. It's seen in every form, shape, and size. It just made sense for us to go after a protein that was widely used."
It's tempting to assume that innovating on pillars of cultural significance might be easier if the focus were on a whole new kind of food to begin with, not your popular dim sum items or fast food offerings. But it's proving to be quite the opposite.
"That could have been one direction where [researchers] just said, 'Look, it's really hard to reproduce raw ground beef. Why don't we just make something completely new, like meat chips?'" says Mike Lee, co-founder and co-CEO of Alpha Food Labs, which works on food innovation more broadly. "While that strategy's interesting, I think we've got so many new things to explain to people that I don't know if you want to also explain this new format of food that you've never, ever seen before."
We've seen this same cautious approach to change before in other ways that relate to cooking. Perhaps the most obvious example is the kitchen range. As Bee Wilson writes in her book Consider the Fork: A History of How We Cook and Eat, in the 1880s, convincing ardent coal-range users to switch to newfangled gas was a hard sell. To win them over, inventor William Sugg designed a range that used gas, but aesthetically looked like the coal ones already in fashion at the time -- and which in some visual ways harkened even further back to the days of open-hearth cooking. Over time, gas range designs moved further away from those of the past, but the initial jump was only made possible through familiarity. There's a cleverness to meeting people where they are.
"New gadgets feel safest when they remind us of other objects that we already know," writes Wilson. "It is far harder to accept a technology that is entirely new."
Maybe someday we won't want anything other than meat chips, but not today.
Measuring Success
A 2018 Gallup poll shows that in the U.S., rates of true vegetarianism and veganism have been stagnant for as long as they've been measured. When the poll began in 1999, six percent of Americans were vegetarian, a number that remained steady until 2012, when the number dropped one point. As of 2018, it remained at five percent.
In 2012, when Gallup first measured the percentage of vegans, the rate was two percent. By 2018 it had gone up just one point, to three percent. Increasing awareness of animal welfare, health, and environmental concerns don't seem to be incentive enough to convince Americans, en masse, to completely slam the door on a food culture characterized in many ways by its emphasis on traditional meat consumption.
"A lot of consumers get over the ick factor when you tell them that most of the food that you're eating right now has entered the lab at some point."
Wilson writes that "experimenting with new foods has always been a dangerous business. In the wild, trying out some tempting new berries might lead to death. A lingering sense of this danger may make us risk-averse in the kitchen."
That might be one psychologically deep-seated reason that Americans are so resistant to ditch meat altogether. But a middle ground is emerging with a rise in flexitarianism, which aims to reduce reliance on traditional animal products. "Americans are eager to include alternatives to animal products in their diets, but are not willing to give up animal products completely," the same 2018 Gallup poll reported. This may represent the best opportunity for lab-grown meat to wedge itself into the culture.
Quantitatively predicting a population's willingness to try a lab-grown version of its favorite protein is proving a hard thing to measure, however, because it's still science fiction to a regular consumer. Measuring popular opinion of something that doesn't really exist yet is a dubious pastime.
In 2015, University of Wisconsin School of Public Health researchers Linnea Laestadius and Mark Caldwell conducted a study using online comments on articles about lab-grown meat to suss out public response to the food. The results showed a mostly negative attitude, but that was only two years into a field that is six years old today. Already public opinion may have shifted.
Shiok Meat's Sriram and her co-founder Ka Yi Ling have used online surveys to get a sense of the landscape, but they also take a more direct approach sometimes. Every time they give a public talk about their company and their shrimp, they poll their audience before and after the talk, using the question, "How many of you are willing to try, and pay, to eat lab-grown meat?"
They consistently find that the percentage of people willing to try goes up from 50 to 90 percent after hearing their talk, which includes information about the downsides of traditional shrimp farming (for one thing, many shrimp are raised in sewage, and peeled and deveined by slaves) and a bit of information about how lab-grown animal protein is being made now. I saw this pan out myself when Ling spoke at a New Harvest conference in Cambridge, Massachusetts in July.
"A lot of consumers get over the ick factor when you tell them that most of the food that you're eating right now has entered the lab at some point," Sriram says. "We're not going to grow our meat in the lab always. It's in the lab right now, because we're in R&D. Once we go into manufacturing ... it's going to be a food manufacturing facility, where a lot of food comes from."
The downside of the University of Wisconsin's and Shiok Meat's approach to capturing public opinion is that they each look at self-selecting groups: Online commenters are often fueled by a need to complain, and it's likely that anyone attending a talk by the co-founders of a lab-grown meat company already has some level of open-mindedness.
So Sriram says that she and Ling are also using another method to assess the landscape, and it's somewhere in the middle. They've been watching public responses to the closest available product to lab-grown meat that's on the market: Impossible Burger. As a 100 percent plant-based burger, it's not quite the same, but this bleedable, searable patty is still very much the product of science and laboratory work. Its remarkable similarity to beef is courtesy of yeast that have been genetically engineered to contain DNA from soy plant roots, which produce a protein called heme as they multiply. This heme is a plant-derived protein that can look and act like the heme found in animal muscle.
So far, the sciencey underpinnings of the burger don't seem to be turning people off. In just four years, it's already found its place within other American food icons. It's readily available everywhere from nationwide Burger Kings to Boston's Warren Tavern, which has been in operation since 1780, is one of the oldest pubs in America, and is even named after the man who sent Paul Revere on his midnight ride. Some people have already grown so attached to the Impossible Burger that they will actually walk out of a restaurant that's out of stock. Demand for the burger is outpacing production.
"Even though [Impossible] doesn't consider their product cellular agriculture, it's part of a spectrum of innovation," Krueger says. "There are novel proteins that you're not going to find in your average food, and there's some cool tech there. So to me, that does show a lot of willingness on people's part to think about trying something new."
The message for those working on animal-based lab-grown meat is clear: People will accept innovation on their favorite food if it tastes good enough and evokes the same emotional connection as the real deal.
"How people talk about lab-grown meat now, it's still a conversation about science, not about culture and emotion," Lee says. But he's confident that the conversation will start to shift in that direction if the companies doing this work can nail the flavor memory, above all.
And then proving how much power flavor lords over us, we quickly derail into a conversation about Doritos, which he calls "maniacally delicious." The chips carry no health value whatsoever and are a native product of food engineering and manufacturing — just watch how hard it is for Bon Appetit associate food editor Claire Saffitz to try and recreate them in the magazine's test kitchen — yet devotees remain unfazed and crunch on.
"It's funny because it shows you that people don't ask questions about how [some foods] are made, so why are they asking so many questions about how lab-grown meat is made?" Lee asks.
For all the hype around Impossible Burger, there are still controversies and hand-wringing around lab-grown meat. Some people are grossed out by the idea, some people are confused, and if you're the U.S. Cattlemen's Association (USCA), you're territorial. Last year, the group sent a petition to the USDA to "exclude products not derived directly from animals raised and slaughtered from the definition of 'beef' and meat.'"
"I think we are probably three or four big food safety scares away from everyone, especially younger generations, embracing lab-grown meat as like, 'Science is good; nature is dirty, and can kill you.'"
"I have this working hypothesis that if you look at the nation in 50-year spurts, we revolve back and forth between artisanal, all-natural food that's unadulterated and pure, and food that's empowered by science," Lee says. "Maybe we've only had one lap around the track on that, but I think we are probably three or four big food safety scares away from everyone, especially younger generations, embracing lab-grown meat as like, 'Science is good; nature is dirty, and can kill you.'"
Food culture goes beyond just the ingredients we know and love — it's also about how we interact with them, produce them, and expect them to taste and feel when we bite down. We accept a margin of difference among a fast food burger, a backyard burger from the grill, and a gourmet burger. Maybe someday we'll accept the difference between a burger created by killing a cow and a burger created by biopsying one.
Looking to the Future
Every time we engage with food, "we are enacting a ritual that binds us to the place we live and to those in our family, both living and dead," Wilson writes in Consider the Fork. "Such things are not easily shrugged off. Every time a new cooking technology has been introduced, however useful … it has been greeted in some quarters with hostility and protestations that the old ways were better and safer."
This is why it might be hard for a vegetarian mother to try her daughter's lab-grown shrimp, no matter how ethically it was produced or how awe-inspiring the invention is. Yet food cultures can and do change. "They're not these static things," says Benjamin Wurgaft, a historian whose book Meat Planet: Artificial Flesh and the Future of Food comes out this month. "The real tension seems to be between slow change and fast change."
In fact, the very definition of the word "meat" has never exclusively meant what the USCA wants it to mean. Before the 12th century, when it first appeared in Old English as "mete," it wasn't very specific at all and could be used to describe anything from "nourishment," to "food item," to "fodder," to "sustenance." By the 13th century it had been narrowed down to mean "flesh of warm-blooded animals killed and used as food." And yet the British mincemeat pie lives on as a sweet Christmas treat full of -- to the surprise of many non-Brits -- spiced, dried fruit. Since 1901, we've also used this word with ease as a general term for anything that's substantive -- as in, "the meat of the matter." There is room for yet more definitions to pile on.
"The conversation [about lab-ground meat] has changed remarkably in the last six years," Wurgaft says. "It has become a conversation about whether or not specific companies will bring a product to market, and that's a really different conversation than asking, 'Should we produce meat in the lab?'"
As part of the field research for his book, Wurgaft visited the Rijksmuseum Boerhaave, a Dutch museum that specializes in the history of science and medicine. It was 2015, and he was there to see an exhibit on the future of food. Just two years earlier, Mark Post had made that first lab-grown hamburger about a two-and-a-half hour drive south of the museum. When Wurgaft arrived, he found the novel invention, which Post had donated to the museum, already preserved and served up on a dinner plate, the whole outfit protected by plexiglass.
"They put this in the exhibit as if it were already part of the historical records, which to a historian looked really weird," Wurgaft says. "It looked like somebody taking the most recent supercomputer and putting it in a museum exhibit saying, 'This is the supercomputer that changed everything,' as if you were already 100 years in the future, looking back."
It seemed to symbolize an effort to codify a lab-grown hamburger as a matter of Dutch pride, perhaps someday occupying a place in people's hearts right next to the stroopwafel.
"Who's to say that we couldn't get a whole school of how to cook with lab-grown meat?"
Lee likes to imagine that part of the legacy of lab-grown meat, if it succeeds, will be to inspire entirely new fads in cooking -- a step beyond ones like the crab-filled avocado of the 1960s or the pesto of the 1980s in the U.S.
"[Lab-grown meat] is inherently going to be a different quality than anything we've done with an animal," he says. "Look at every cut [of meat] on the sphere today -- each requires a slightly different cooking method to optimize the flavor of that cut. Who's to say that we couldn't get a whole school of how to cook with lab-grown meat?"
At this point, most of us have no way of trying lab-grown meat. It remains exclusively available through sometimes gimmicky demos reserved for investors and the media. But Wurgaft says the stories we tell about this innovation, the articles we write, the films we make, and yes, even the museum exhibits we curate, all hold as much cultural significance as the product itself might someday.
Is there a robot nanny in your child's future?
From ROBOTS AND THE PEOPLE WHO LOVE THEM: Holding on to Our Humanity in an Age of Social Robots by Eve Herold. Copyright © 2024 by the author and reprinted by permission of St. Martin’s Publishing Group.
Could the use of robots take some of the workload off teachers, add engagement among students, and ultimately invigorate learning by taking it to a new level that is more consonant with the everyday experiences of young people? Do robots have the potential to become full-fledged educators and further push human teachers out of the profession? The preponderance of opinion on this subject is that, just as AI and medical technology are not going to eliminate doctors, robot teachers will never replace human teachers. Rather, they will change the job of teaching.
A 2017 study led by Google executive James Manyika suggested that skills like creativity, emotional intelligence, and communication will always be needed in the classroom and that robots aren’t likely to provide them at the same level that humans naturally do. But robot teachers do bring advantages, such as a depth of subject knowledge that teachers can’t match, and they’re great for student engagement.
The teacher and robot can complement each other in new ways, with the teacher facilitating interactions between robots and students. So far, this is the case with teaching “assistants” being adopted now in China, Japan, the U.S., and Europe. In this scenario, the robot (usually the SoftBank child-size robot NAO) is a tool for teaching mainly science, technology, engineering, and math (the STEM subjects), but the teacher is very involved in planning, overseeing, and evaluating progress. The students get an entertaining and enriched learning experience, and some of the teaching load is taken off the teacher. At least, that’s what researchers have been able to observe so far.
To be sure, there are some powerful arguments for having robots in the classroom. A not-to-be-underestimated one is that robots “speak the language” of today’s children, who have been steeped in technology since birth. These children are adept at navigating a media-rich environment that is highly visual and interactive. They are plugged into the Internet 24-7. They consume music, games, and huge numbers of videos on a weekly basis. They expect to be dazzled because they are used to being dazzled by more and more spectacular displays of digital artistry. Education has to compete with social media and the entertainment vehicles of students’ everyday lives.
Another compelling argument for teaching robots is that they help prepare students for the technological realities they will encounter in the real world when robots will be ubiquitous. From childhood on, they will be interacting and collaborating with robots in every sphere of their lives from the jobs they do to dealing with retail robots and helper robots in the home. Including robots in the classroom is one way of making sure that children of all socioeconomic backgrounds will be better prepared for a highly automated age, when successfully using robots will be as essential as reading and writing. We’ve already crossed this threshold with computers and smartphones.
Students need multimedia entertainment with their teaching. This is something robots can provide through their ability to connect to the Internet and act as a centralized host to videos, music, and games. Children also need interaction, something robots can deliver up to a point, but which humans can surpass. The education of a child is not just intended to make them technologically functional in a wired world, it’s to help them grow in intellectual, creative, social, and emotional ways. When considered through this perspective, it opens the door to questions concerning just how far robots should go. Robots don’t just teach and engage children; they’re designed to tug at their heartstrings.
It’s no coincidence that many toy makers and manufacturers are designing cute robots that look and behave like real children or animals, says Turkle. “When they make eye contact and gesture toward us, they predispose us to view them as thinking and caring,” she has written in The Washington Post. “They are designed to be cute, to provide a nurturing response” from the child. As mentioned previously, this nurturing experience is a powerful vehicle for drawing children in and promoting strong attachment. But should children really love their robots?
ROBOTS AND THE PEOPLE WHO LOVE THEM: Holding on to Our Humanity in an Age of Social Robots by Eve Herold (January 9, 2024).
St. Martin’s Publishing Group
The problem, once again, is that a child can be lulled into thinking that she’s in an actual relationship, when a robot can’t possibly love her back. If adults have these vulnerabilities, what might such asymmetrical relationships do to the emotional development of a small child? Turkle notes that while we tend to ascribe a mind and emotions to a socially interactive robot, “simulated thinking may be thinking, but simulated feeling is never feeling, and simulated love is never love.”
Always a consideration is the fact that in the first few years of life, a child’s brain is undergoing rapid growth and development that will form the foundation of their lifelong emotional health. These formative experiences are literally shaping the child’s brain, their expectations, and their view of the world and their place in it. In Alone Together, Turkle asks: What are we saying to children about their importance to us when we’re willing to outsource their care to a robot? A child might be superficially entertained by the robot while his self-esteem is systematically undermined.
Research has emerged showing that there are clear downsides to child-robot relationships.
Still, in the case of robot nannies in the home, is active, playful engagement with a robot for a few hours a day any more harmful than several hours in front of a TV or with an iPad? Some, like Xiong, regard interacting with a robot as better than mere passive entertainment. iPal’s manufacturers say that their robot can’t replace parents or teachers and is best used by three- to eight-year-olds after school, while they wait for their parents to get off work. But as robots become ever-more sophisticated, they’re expected to perform more of the tasks of day-to-day care and to be much more emotionally advanced. There is no question children will form deep attachments to some of them. And research has emerged showing that there are clear downsides to child-robot relationships.
Some studies, performed by Turkle and fellow MIT colleague Cynthia Breazeal, have revealed a darker side to the child-robot bond. Turkle has reported extensively on these studies in The Washington Post and in her book Alone Together. Most children love robots, but some act out their inner bully on the hapless machines, hitting and kicking them and otherwise trying to hurt them. The trouble is that the robot can’t fight back, teaching children that they can bully and abuse without consequences. As in any other robot relationship, such harmful behavior could carry over into the child’s human relationships.
And, ironically, it turns out that communicative machines don’t actually teach kids good communication skills. It’s well known that parent-child communication in the first three years of life sets the stage for a very young child’s intellectual and academic success. Verbal back-and-forth with parents and care-givers is like fuel for a child’s growing brain. One article that examined several types of play and their effect on children’s communication skills, published in JAMA Pediatrics in 2015, showed that babies who played with electronic toys—like the popular robot dog Aibo—show a decrease in both the quantity and quality of their language skills.
Anna V. Sosa of the Child Speech and Language Lab at Northern Arizona University studied twenty-six ten- to sixteen- month-old infants to compare the growth of their language skills after they played with three types of toys: electronic toys like a baby laptop and talking farm; traditional toys like wooden puzzles and building blocks; and books read aloud by their parents. The play that produced the most growth in verbal ability was having books read to them by a caregiver, followed by play with traditional toys. Language gains after playing with electronic toys came dead last. This form of play involved the least use of adult words, the least conversational turntaking, and the least verbalizations from the children. While the study sample was small, it’s not hard to extrapolate that no electronic toy or even more abled robot could supply the intimate responsiveness of a parent reading stories to a child, explaining new words, answering the child’s questions, and modeling the kind of back- and-forth interaction that promotes empathy and reciprocity in relationships.
***
Most experts acknowledge that robots can be valuable educational tools. But they can’t make a child feel truly loved, validated, and valued. That’s the job of parents, and when parents abdicate this responsibility, it’s not only the child who misses out on one of life’s most profound experiences.
We really don’t know how the tech-savvy children of today will ultimately process their attachments to robots and whether they will be excessively predisposed to choosing robot companionship over that of humans. It’s possible their techno literacy will draw for them a bold line between real life and a quasi-imaginary history with a robot. But it will be decades before we see long-term studies culminating in sufficient data to help scientists, and the rest of us, to parse out the effects of a lifetime spent with robots.
This is an excerpt from ROBOTS AND THE PEOPLE WHO LOVE THEM: Holding on to Our Humanity in an Age of Social Robots by Eve Herold. The book will be published on January 9, 2024.
Story by Big Think
In rare cases, a woman’s heart can start to fail in the months before or after giving birth. The all-important muscle weakens as its chambers enlarge, reducing the amount of blood pumped with each beat. Peripartum cardiomyopathy can threaten the lives of both mother and child. Viral illness, nutritional deficiency, the bodily stress of pregnancy, or an abnormal immune response could all play a role, but the causes aren’t concretely known.
If there is a silver lining to peripartum cardiomyopathy, it’s that it is perhaps the most survivable form of heart failure. A remarkable 50% of women recover spontaneously. And there’s an even more remarkable explanation for that glowing statistic: The fetus‘ stem cells migrate to the heart and regenerate the beleaguered muscle. In essence, the developing or recently born child saves its mother’s life.
Saving mama
While this process has not been observed directly in humans, it has been witnessed in mice. In a 2015 study, researchers tracked stem cells from fetal mice as they traveled to mothers’ damaged cardiac cells and integrated themselves into hearts.
Evolutionarily, this function makes sense: It is in the fetus’ best interest that its mother remains healthy.
Scientists also have spotted cells from the fetus within the hearts of human mothers, as well as countless other places inside the body, including the skin, spleen, liver, brain, lung, kidney, thyroid, lymph nodes, salivary glands, gallbladder, and intestine. These cells essentially get everywhere. While most are eliminated by the immune system during pregnancy, some can persist for an incredibly long time — up to three decades after childbirth.
This integration of the fetus’ cells into the mother’s body has been given a name: fetal microchimerism. The process appears to start between the fourth and sixth week of gestation in humans. Scientists are actively trying to suss out its purpose. Fetal stem cells, which can differentiate into all sorts of specialized cells, appear to target areas of injury. So their role in healing seems apparent. Evolutionarily, this function makes sense: It is in the fetus’ best interest that its mother remains healthy.
Sending cells into the mother’s body may also prime her immune system to grow more tolerant of the developing fetus. Successful pregnancy requires that the immune system not see the fetus as an interloper and thus dispatch cells to attack it.
Fetal microchimerism
But fetal microchimerism might not be entirely beneficial. Greater concentrations of the cells have been associated with various autoimmune diseases such as lupus, Sjogren’s syndrome, and even multiple sclerosis. After all, they are foreign cells living in the mother’s body, so it’s possible that they might trigger subtle, yet constant inflammation. Fetal cells also have been linked to cancer, although it isn’t clear whether they abet or hinder the disease.
A team of Spanish scientists summarized the apparent give and take of fetal microchimerism in a 2022 review article. “On the one hand, fetal microchimerism could be a source of progenitor cells with a beneficial effect on the mother’s health by intervening in tissue repair, angiogenesis, or neurogenesis. On the other hand, fetal microchimerism might have a detrimental function by activating the immune response and contributing to autoimmune diseases,” they wrote.
Regardless of a fetus’ cells net effect, their existence alone is intriguing. In a paper published earlier this year, University of London biologist Francisco Úbeda and University of Western Ontario mathematical biologist Geoff Wild noted that these cells might very well persist within mothers for life.
“Therefore, throughout their reproductive lives, mothers accumulate fetal cells from each of their past pregnancies including those resulting in miscarriages. Furthermore, mothers inherit, from their own mothers, a pool of cells contributed by all fetuses carried by their mothers, often referred to as grandmaternal microchimerism.”
So every mother may carry within her literal pieces of her ancestors.