Are Flat Feet Hereditary? The Role of Genetics

Flat feet run in families, and genetics clearly contribute to foot arch shape, but researchers have not yet identified the specific genes responsible. A 2024 systematic review searching for genetic variants directly linked to foot arch height came up empty: out of nineteen eligible studies spanning more than a decade, not a single one had pinpointed gene variants that determine whether someone develops a high arch or a flat one.¹ That is a striking gap for a trait so common and so visibly heritable. The honest answer is that flat feet are partly genetic, but the genetics are tangled up with childhood development, body weight, footwear habits, and the health of your tendons and connective tissue in ways that make “hereditary” a much messier label than it sounds.

What Genetic Research Has and Has Not Found

The idea that flat feet are inherited is old and intuitive. Parents with flat feet often notice the same trait in their children. Twin studies and family clustering data support a heritable component, and the trait clearly does not follow a simple one-gene pattern. It behaves more like height or body shape: many genes each nudge the outcome a little, and the environment fills in the rest.

Where the science gets frustrating is at the molecular level. That 2024 review looked specifically for single nucleotide polymorphisms, the tiny DNA variations that distinguish one person’s genetic blueprint from another’s, and found 137 of them across the studies reviewed. But all of those variants were associated with broader genetic conditions that happen to affect the foot, like connective tissue disorders or nerve diseases, rather than with foot arch shape directly. No one has yet run a large genome-wide study asking “which gene variants make a person more likely to have flat feet in the absence of a diagnosable syndrome?”¹ That is the missing study, and until it is done, genetics can only explain flat feet indirectly.

One indirect clue comes from collagen genes. A variant called rs12722, linked to collagen genes COL3A1 and COL5A1, has been repeatedly associated with increased joint range of motion across populations of both East Asian and European descent.² More flexible joints tend to produce looser ligaments, and looser ligaments in the foot can let the arch flatten under load. This is not the same as saying the variant “causes” flat feet, but it illustrates the kind of genetic pathway that researchers suspect is involved: genes shaping collagen quality, which shapes tissue stiffness, which shapes arch height.

Connective Tissue Disorders as a Window Into Genetics

The strongest genetic signal for flat feet currently comes from people with diagnosed connective tissue conditions. Ehlers-Danlos syndrome, a group of inherited disorders affecting collagen, is a vivid example. In one study comparing people with EDS to a matched group without it, flat feet were reported in roughly 55% of the EDS group versus just 8% of the comparison group.³ That is a sevenfold difference, and it shows that when collagen is genetically compromised, the arch almost predictably collapses.

Marfan syndrome, another connective tissue condition, tells a similar story. The same systematic review noted that flat feet were consistently linked to connective tissue disorders, while the opposite foot shape, high arches, tended to appear alongside nerve and muscle diseases like Charcot-Marie-Tooth disease.² These extremes suggest that the spectrum from flat to high arch is at least partly governed by how well your connective tissue resists mechanical loading, and connective tissue quality is heavily genetic.

For the average person with flat feet, though, these syndromic cases are the far end of the bell curve. Most flat feet are “flexible,” meaning the arch appears when the foot is off the ground and flattens under weight. That is a much milder version of the same tissue-laxity phenomenon, and it is unlikely to trace back to a single dramatic mutation. It is more likely a combination of many small genetic contributions plus environmental loading.

How Arches Develop in Childhood

One reason flat feet can look hereditary even when genetics are only part of the story is timing. Nearly all toddlers have flat feet. The arch develops gradually through childhood, and the pace varies enormously from one child to the next. A large study measuring over 10,000 children found that the arch height ratio stayed essentially flat until age 10 or 11 in girls and 11 in boys, then rose noticeably during the early teen years before plateauing around 12 to 14.⁴ So a seven-year-old with apparently flat feet may simply be on the slower end of a normal developmental curve.

A longitudinal study tracking 263 children who started with flat feet found that some developed arches over 18 months while others stayed flat. The children whose arches developed had started with a less severe degree of flatness, and boys who developed arches also showed better single-leg balance.⁵ That suggests arch development is not just a genetic switch flipping on at puberty. It is wrapped up in musculoskeletal maturation, body composition, and neuromuscular coordination, all of which are themselves influenced by both genes and the child’s activity patterns.

If one parent had flat feet as a child and outgrew them, and the other parent did not, their child’s trajectory is genuinely hard to predict. The inherited contribution blends with everything else happening during growth. Pediatricians generally advise against treating painless flat feet in young children for this reason; many will resolve on their own.

Environmental Factors That Shape the Arch

Even with identical genetics, your feet do not develop in a vacuum. Two environmental factors stand out in the research: footwear and body weight.

A longitudinal study of children aged seven to nine found that those who wore closed-toe shoes had the lowest overall arch measurements, while those who wore sandals had slightly higher arches. Children who wore slippers during the toddler years ended up with flatter arches in later childhood compared to those who wore sandals.⁶ The idea is that less rigid footwear allows the foot’s intrinsic muscles to work harder, strengthening the arch over time, while stiff shoes do the supporting work the muscles should be doing. Populations that habitually go barefoot tend to have higher arches on average, which is consistent with this explanation.

Body weight has an even clearer link. A Mendelian randomization study, which uses genetic variants associated with obesity as a kind of natural experiment, found that higher BMI was associated with about an 80% increase in the odds of flat feet. Larger waist and hip circumference independently raised the risk as well.⁷ Because this study design uses genetic instruments rather than just observing correlations, the evidence is stronger than “heavier people tend to have flatter feet.” It suggests the extra load actually pushes the arch down over time. That means a person genetically predisposed to flat feet who also carries extra weight faces a double hit.

Population Differences in Prevalence

Flat feet are not equally common across demographic groups, and the pattern hints at genetic ancestry playing a role alongside environment. In the Johnston County Osteoarthritis Project, which compared foot types in a community sample of African American and white adults, flat feet were roughly three times more common in African Americans after adjusting for age, sex, BMI, and education. Meanwhile, high arches were about four times more common in white participants.⁸ Those are large differences that persist after accounting for body weight, suggesting that structural or genetic factors beyond obesity contribute.

Geography and altitude may add further nuance. A study of Colombian schoolchildren found a prevalence of about 21% in Bogotá, a high-altitude city, compared to about 8% in Barranquilla at sea level. Boys had higher rates than girls, and increasing BMI was again an associated factor. Younger children had higher prevalence, consistent with the developmental timeline discussed earlier.⁹ Disentangling genetics from shared family environments, shoe-wearing customs, and activity levels across populations remains an open challenge.

Flat Feet That Develop in Adulthood

Not all flat feet are present from childhood. Adult-acquired flatfoot deformity is a distinct condition, typically caused by progressive failure of the posterior tibial tendon, the tendon that runs along the inside of the ankle and holds the arch up. It is more common in women, particularly after middle age, and is associated with obesity, diabetes, and hypertension.¹⁰

Genetics enter the picture here through hormonal pathways. A case-control study of postmenopausal women found that a specific variant in the estrogen receptor gene was associated with posterior tibial tendon problems, suggesting that genetic differences in how tissues respond to hormonal changes after menopause can predispose certain women to tendon breakdown and arch collapse.¹¹ This is a reminder that “hereditary” does not always mean “born with it.” Genetic susceptibility can stay silent for decades and only manifest when the right trigger, like hormonal shifts or accumulated mechanical stress, comes along.

The Hypermobility Question

A common assumption is that joint hypermobility, being “double-jointed,” automatically leads to flat feet. The logic sounds airtight: looser joints, looser ligaments in the foot, flatter arch. And the EDS data supports this at the extreme end. But in typical children the relationship is weaker than expected. A study of preschool-aged children found no correlation between general joint hypermobility scores and flatfoot when using standard clinical measures.¹² The researchers tried multiple ways of measuring hypermobility and still came up with no link.

This does not mean ligament laxity is irrelevant to arch shape. It probably means that in the general population, the degree of laxity varies within a range too narrow to reliably predict foot type. The dramatic effect seen in EDS may require a threshold of tissue disruption that most hypermobile children do not reach. For parents wondering whether a bendy toddler is destined for flat feet, the evidence says probably not, at least not on that basis alone.

What Flat Feet Actually Do to the Body

Whether you inherited your flat feet or acquired them, the downstream effects on the rest of the body are the same. People with flat feet show reduced balance stability, particularly when they cannot rely on vision. One study found that a stability measure dropped significantly in the flat-foot group during single-leg standing with eyes closed compared to those with normal arches.¹³

The effects can climb the chain. In children, flatter foot posture was associated with increased odds of knee symptoms and hip or back discomfort, along with changes in walking mechanics including increased knee inward tilt at midstance.¹⁴ In adults, a meta-analysis found strong evidence of an association between flat feet and low back pain, with moderate and severe cases showing higher rates of back pain than mild cases or people with normal arches.¹⁵ None of this means flat feet inevitably cause pain. Plenty of people with very flat feet walk through life without any symptoms. But when problems do appear, the arch is worth examining as a contributing factor.

Managing Flat Feet When They Cause Problems

If flat feet are painless and do not limit activity, treatment is rarely needed, regardless of whether the trait was inherited. The threshold for intervention is symptoms: foot pain, ankle fatigue, difficulty with prolonged standing or walking, or problems in the knees, hips, or back that trace back to foot alignment.

For symptomatic flexible flat feet, two approaches have the best evidence. Short foot exercises, which involve actively contracting the muscles of the sole to raise the arch without curling the toes, have been shown to improve arch height and reduce pain.¹⁶ Foot orthoses, custom or off-the-shelf insoles that support the arch, also help. A randomized trial found that combining short foot exercises with orthoses for six weeks produced better results in pain, function, and foot pressure distribution than orthoses alone.¹⁷

An eight-week trial comparing lower-extremity strengthening exercises to foot orthoses found that both improved arch height and balance, but the exercise group showed superior results.¹⁸ That is an encouraging finding for people with hereditary flat feet who wonder whether the structure of their foot is unchangeable. The arch is not just a passive bony framework; it is actively held up by muscles, and those muscles respond to training. Genetics may set the starting point, but strengthening can shift the outcome.

Surgery is reserved for cases where conservative treatment fails and the deformity is severe or progressive. For the rare patient whose flat feet stem from a condition like hypermobile Ehlers-Danlos syndrome, surgical planning gets more complicated. A case report and literature review noted that standard pediatric flatfoot reconstruction techniques may not hold in EDS patients because their tissue simply cannot maintain the correction. More aggressive procedures, including joint fusion, may be needed to produce a lasting result.¹⁹

How the Arch Evolved in the First Place

The longitudinal arch of the human foot is an evolutionary innovation tied to walking upright. Early hominin feet were grasping appendages, more like a chimpanzee’s foot than a modern human’s. Over millions of years, the foot stiffened and developed an arch that stores elastic energy during walking and running, functioning as a kind of spring that returns energy with each step.²⁰ Analysis of fossils attributed to Australopithecus afarensis, the species that includes the famous “Lucy” skeleton, suggests that even our upright-walking ancestors may have had flatter feet than modern humans, with the fully stiffened arch coming later in the evolutionary timeline.

This evolutionary context is useful because it puts modern variation in perspective. The arch is not an all-or-nothing structure. It exists on a continuum, and variation within that continuum has been present for as long as humans have been walking. Flat feet are not a “defect” any more than being at the shorter end of the height distribution is a defect. They sit at one end of a range that natural selection has tolerated, and in many cases encouraged, because the fitness cost of moderate arch flattening is negligible when pain is absent and mobility is intact.

How Muscles Adapt in Flat Feet

Genetics and development set the stage, but muscles respond dynamically to the foot structure they find themselves in. Research comparing the foot muscles of people with flat feet to those with normal arches found measurable differences under load. The peroneus brevis, a muscle on the outer lower leg, was larger in the flat-foot group across all loading conditions. Meanwhile, the intrinsic foot muscles, including the abductor hallucis and flexor digitorum brevis, shrank more under increasing load in the flat-foot group, and the stiffness of certain muscles was higher under heavy loads.²¹ In other words, flat feet do not just passively flatten. The muscles around them compensate, and those compensatory patterns can contribute to fatigue and discomfort during prolonged activity. This is also why targeted strengthening of the intrinsic foot muscles, as discussed earlier, can make a meaningful difference even in an architecturally flat foot.