Babies are born with a fully functional sense of taste and, in fact, start developing taste buds long before birth. The structures that allow taste perception begin forming during the first trimester of pregnancy, and by around week 14 or 15 of gestation, most taste pores on the tongue are already in place. Newborns actually arrive with roughly 10,000 taste buds spread more widely across the mouth than an adult’s, making them surprisingly sensitive tasters from the moment they take their first breath.
How Taste Buds Form in the Womb
Taste bud development follows a fairly brisk timeline. Nerve fibers begin reaching toward the surface of the tongue between the sixth and seventh week after conception. By the eighth week, those nerves have pushed through the tissue and started forming connections with early taste cells. Around the twelfth week, more specialized cell types appear, including cells that will eventually detect sour tastes and cells involved in sensing sweet, bitter, and umami flavors. The taste pores themselves, the tiny openings on the tongue’s surface where saliva carries dissolved chemicals to receptor cells, mostly develop by the fourteenth to fifteenth week.1PubMed. Embryonic and early fetal development of human taste buds: a transmission electron microscopical study
What’s striking about this timeline is how early the hardware is in place relative to when a baby is actually born. A fetus at 15 weeks still has roughly 25 weeks of development ahead, yet taste structures are already wired up and beginning to function. The nerve connections between taste cells and the brain reach their peak density around weeks 12 to 13, well into the first trimester.1PubMed. Embryonic and early fetal development of human taste buds: a transmission electron microscopical study That said, having the structures in place doesn’t mean they work at full adult capacity right away. Research has noted that while the anatomy develops early, adult-level function and adult-sized taste structures take longer to mature.2PubMed. Taste development: differential growth rates of tongue regions in humans
Tasting Flavors Before Birth
Because the fetus constantly swallows amniotic fluid, and because that fluid picks up chemical traces of whatever the mother eats, babies get their first flavor experiences months before they eat any food. Studies have shown that maternal diet genuinely changes the chemical composition of amniotic fluid. In one experiment, pregnant women who swallowed garlic capsules about 45 minutes before an amniocentesis procedure produced amniotic fluid that a panel of adults could reliably identify as smelling like garlic compared with fluid from women who took placebo capsules.3Chemical Senses. Garlic Ingestion by Pregnant Women Alters the Odor of Amniotic Fluid
More recently, researchers used ultrasound imaging to show that fetuses don’t just passively encounter these flavors; they react to them. Between 32 and 36 weeks of gestation, fetuses whose mothers had consumed a carrot-flavored capsule were more likely to make facial movements associated with smiling and laughter. Fetuses exposed to kale, on the other hand, more frequently showed facial movements linked to crying and lip pressing.4PubMed. Flavor Sensing in Utero and Emerging Discriminative Behaviors in the Human Fetus These weren’t subtle statistical patterns buried in noise. The differences between the carrot and kale groups were clear enough to be measured frame by frame on ultrasound. Fetuses, it seems, already have opinions about vegetables.
What Newborns Can Taste Right Away
Babies don’t arrive as blank slates when it comes to taste. They come pre-loaded with strong preferences that appear to be hardwired. Newborns consistently show positive responses to sweet and negative responses to bitter flavors.5PubMed Central. Early Taste Experiences and Later Food Choices The preference for sweet is thought to have evolved because sweetness typically signals energy-dense, calorie-rich foods, while bitterness often flags potentially toxic plants. For an organism that can’t read labels or ask questions about what it’s eating, these built-in preferences serve as a rough safety guide.6PubMed Central. The sweetness and bitterness of childhood: Insights from basic research on taste preferences
Researchers have documented these reactions in striking detail. In a study of infants between five and eight weeks old, facial muscle activity was recorded while the babies tasted different solutions. Almost all of the infants, close to 100%, showed measurable facial responses to the unpleasant tastes of quinine (bitter) and citric acid (sour), while about 80% responded to sucrose (sweet).7Chemical Senses. Taste-Elicited Activity in Facial Muscle Regions in 5–8-Week-Old Infants The reactions weren’t identical across tastes. Multiple facial muscle regions fired simultaneously but in different patterns depending on whether the flavor was pleasant or unpleasant, suggesting the discrimination is real and not just a generic startle response.
Umami, the savory taste associated with protein-rich foods, is another flavor newborns seem to detect. Infant studies have found that adding a umami compound to soup makes it preferred over soup alone, even though the compound dissolved in plain water isn’t preferred over water by itself.8PubMed Central. Development and genetics of glutamate taste preference In other words, babies seem to appreciate umami in the same contextual way adults do: it enhances food rather than tasting good on its own. The liking for sweet, salty, and umami flavors alongside a dislike for bitter appears to be a basic part of human sensory wiring from the start.9PubMed Central. Flavor perception in human infants: development and functional significance
Salt Preference Doesn’t Show Up Immediately
One interesting exception to the “born with it” pattern is salt. Unlike sweetness, which newborns respond to right away, salt preference takes a few months to emerge. Infants around three to four months old begin showing a detectable preference for salty solutions over plain water, and this appears to be an unlearned biological response rather than something shaped by early feeding.10PubMed Central. Infants’ and Children’s Salt Taste Perception and Liking: A Review Before that age, babies seem indifferent to or even mildly averse to salty solutions.
Why the delay? The receptor systems and neural pathways involved in detecting salt appear to mature on a slightly different schedule than those for sweet and bitter. This is worth knowing for parents, because it means the absence of a salt response in a very young infant doesn’t signal anything wrong. It’s simply a taste channel that comes online a bit later than the others.
How Breast Milk Carries the Mother’s Diet
The flavor education that begins with amniotic fluid continues after birth through breast milk. A systematic review found moderate evidence that flavors from the maternal diet, including garlic, carrot, mint, anise, caraway, and eucalyptus, transfer into breast milk in a time-dependent way.11PubMed. Influence of maternal diet on flavor transfer to amniotic fluid and breast milk and children’s responses: a systematic review The flavor profile of breast milk isn’t static; it shifts from feeding to feeding based on what the mother has recently eaten.12PubMed. Diet-Induced Flavor Changes in Human Milk: Update and Perspectives
This gives breastfed babies a continuously changing palette of tastes, which is thought to help prepare them for the transition to solid foods. Each nursing session becomes a small preview of the household diet. A mother who regularly eats a diverse diet introduces her infant to a wider range of flavor compounds, and evidence suggests these early experiences may shape food preferences later on.13PubMed Central. Early Influences on Development of Sensory Perception and Eating Habits Exposure to flavor variety during pregnancy and breastfeeding may improve dietary outcomes down the line, although the degree of flavor transfer varies between individuals.14PubMed. The impact of flavour exposure in utero and during milk feeding on food acceptance at weaning and beyond
Formula-Fed Babies Get a Different Flavor Story
Formula-fed infants have a notably different early taste experience because formula has a more consistent, less varied flavor than breast milk. But the type of formula matters more than people might expect. Infants fed hydrolyzed casein formulas, which have a distinctly bitter and savory taste due to broken-down proteins, develop measurably different taste responses compared with those fed standard milk-based formulas. In studies of babies not yet eating table foods, hydrolyzed-formula-fed infants ate more of savory, bitter, and sour-tasting cereals and showed fewer facial expressions of distaste while eating them.15PubMed Central. Early milk feeding influences taste acceptance and liking during infancy
The effects persist for years. Children who had been fed hydrolyzed protein formulas as infants were more likely to prefer sour-flavored juices and less likely to grimace during taste tests when evaluated several years after they had stopped drinking formula. Children who had been fed soy-based formulas showed a preference for bitter-flavored apple juice. Mothers of children in both the hydrolyzed and soy formula groups also reported that their children were more likely to enjoy broccoli compared with children who had been on standard milk formulas.16PubMed Central. Flavor experiences during formula feeding are related to preferences during childhood The takeaway is that what tastes “normal” to a young infant calibrates their palate in ways that persist well beyond the bottle stage.
There’s a nuance worth noting, though. Hydrolyzed-formula infants who were later introduced to vegetables consumed less broccoli and cauliflower relative to carrots compared with milk-formula infants, and their mothers were about twice as likely to report that their baby didn’t enjoy the brassica vegetables.17PubMed Central. Vegetable acceptance by infants: effects of formula flavors This is consistent with a kind of flavor-specific satiety: if a baby has already been flooded with bitter and savory notes from its formula, it may be less enthusiastic about those same notes showing up in vegetables. Early taste experience isn’t just about more exposure equals more acceptance. Context and variety seem to matter.
Why Some Babies Reject Bitter Foods More Than Others
Not all babies experience bitterness with the same intensity. A gene called TAS2R38 encodes a taste receptor that detects bitter chemicals found in certain vegetables, and common variations in this gene change how strongly a person perceives that bitterness. Some people are strong bitter tasters, some are intermediate, and some barely detect the bitterness at all. These differences are present from infancy and have measurable effects on feeding behavior. In one study, about 31% of infants genetically insensitive to the relevant bitter compound finished a whole complementary meal on their first attempt, compared with only 13% of bitter-sensitive infants.18PubMed Central. TAS2R38 bitter taste genotype is associated with complementary feeding behavior in infants The difference held regardless of whether the baby was breastfed or what specific foods were in the meal.
In adults, the amount of TAS2R38 receptor protein expressed in taste cells directly correlates with how bitter someone rates foods like broccoli juice and substances like quinine.19The American Journal of Clinical Nutrition. Human bitter perception correlates with bitter receptor messenger RNA expression in taste cells And this genetic predisposition doesn’t just affect raw perception; it also predicts how people respond to dietary advice. In a community nutrition intervention, participants who were genetically insensitive to bitterness increased their vegetable consumption the most, while strong bitter tasters in a minimal-intervention group actually decreased theirs.20PubMed Central. TAS2R38 Predisposition to Bitter Taste Associated with Differential Changes in Vegetable Intake in Response to a Community-Based Dietary Intervention
For parents, this means that a baby who consistently rejects green vegetables may not be “picky” in a behavioral sense. They may literally be tasting something more intense than you are. Understanding that there’s a genetic component can help reframe the situation: it’s not defiance, it’s biology. Repeated gentle exposure and pairing bitter vegetables with flavors the baby already enjoys tend to be more productive strategies than simply insisting.
Premature Babies and Taste
Because taste structures develop so early in pregnancy, even premature infants can detect flavors. In a study of preterm babies with an average gestational age of about 35 and a half weeks who had never been fed by mouth (they received all nutrition through a gastric tube), seven out of eight showed a stronger sucking response to glucose solution than to plain water from the very first trial.21Early Human Development. Discrimination of taste and preference for sweet in premature babies The sucking response to glucose also increased with repeated exposure, while the response to water stayed flat. The researchers concluded that the ability to distinguish sweet from non-sweet and a preference for sweetness are present even without any prior oral feeding experience, pointing to a genetic basis.
That said, premature infants can face challenges with taste and feeding that full-term babies don’t. The immaturity of their taste buds and sensory pathways can lead to delayed maturation of taste perception and altered feeding behaviors.22European Journal of Medical and Health Sciences. Unraveling the Physiology of Taste Sensation in Newborns: Mechanisms, Development, and Clinical Implications – Section: Challenges for the High-Risk Neonate Regarding Taste Sensation For babies born very early, the period of tube feeding means they miss out on the normal oral flavor experiences that full-term infants accumulate in the final weeks of pregnancy and during early breastfeeding. Clinicians working with premature infants sometimes consider small amounts of non-nutritive oral stimulation with breast milk to help bridge this gap, though practices vary across hospitals.
Taste Buds Outside the Tongue
When most people picture taste buds, they imagine the tongue. But babies, and adults for that matter, have taste receptors in places that might seem surprising. Researchers studying human tissue from the arytenoid region of the larynx (the cartilage structure near the vocal cords) found many taste buds containing cells that detect bitter, sweet, and umami flavors, along with acid-responsive cells.23PubMed Central. Chemical receptors of the arytenoid: A comparison of human and mouse These taste buds are innervated by nerve fibers, meaning they’re functional sensory equipment, not developmental leftovers.
In infants, having taste receptors near the airway entrance is thought to serve a protective role. If food or liquid starts heading toward the lungs rather than the stomach, bitter or sour receptors in the larynx can trigger reflexive swallowing or coughing to redirect the material. Newborns have about 10,000 taste buds distributed more broadly across the mouth and throat than adults do.24PubMed. The Development of Healthy Eating and Food Pleasure in Infancy Over time, many of the taste buds on the palate, inner cheeks, and throat diminish, concentrating taste perception more on the tongue as the child grows. But in those first months and years, the wider distribution means that a baby’s entire oral cavity is participating in taste in a way that yours no longer does.