Cheek dimples are a normal anatomical variation, not a birth defect. They result from a structural quirk in a facial muscle and are inherited as a dominant genetic trait, appearing in a sizable share of the population. The question is worth asking, though, because the line between “harmless variant” and “medical concern” is not always obvious, and the answer depends partly on which type of dimple you mean.
What Actually Creates a Cheek Dimple
A cheek dimple forms because of the zygomaticus major, one of the main muscles responsible for pulling the corners of your mouth upward when you smile. In most people, this muscle is a single continuous band running from the cheekbone to the corner of the mouth. In people with dimples, the muscle is split, or bifid, with a fork in its fibers that attaches directly to the skin of the cheek.1PubMed. Prevalence of Bifid Zygomaticus Major Muscle When the muscle contracts during a smile, the split fibers pull the overlying skin inward at the point where they attach, creating the visible indentation.2PubMed Central. Anatomical basis of dimple creation – A new technique: Our experience of 100 cases
This is not damage or malformation. It is simply the way the muscle developed in utero. Think of it the way you would think of someone being born with a widow’s peak hairline or attached earlobes: a structural variation with no functional consequence. The muscle still works perfectly fine. It just happens to tug on the skin in a way that creates a cosmetically distinctive feature.
How Dimples Are Inherited
Dimples are generally described as an autosomal dominant trait, meaning a person who inherits the relevant gene variant from even one parent can develop them.3PubMed Central. Evaluation of Prevalence and Morphology of Dimple among Population of Sullia Taluk That said, the inheritance pattern is not as clean and predictable as a classic textbook example. Two parents with dimples can have a child without them, and occasionally two parents without dimples produce a child who has them. This variability suggests that dimples are influenced by more than one gene, or that the expression of the trait depends on other developmental factors that genetics alone cannot fully explain.
The science here is surprisingly thin. No large genome-wide association study has pinpointed the specific genes responsible for cheek dimples in the way that researchers have mapped genes for eye color or certain diseases. The “autosomal dominant” label comes from older family-based observations and smaller studies, not from modern genomic analysis. It holds up as a rough description of how dimples tend to run in families, but the full genetic picture is still incomplete. Researchers have not invested heavily in dimple genetics, likely because the trait is medically harmless and does not affect health outcomes.
Why Most People Have a Dimple on Only One Side
If dimples were purely genetic and purely dominant, you might expect them to show up symmetrically. But they often do not. In a study of people with cheek dimples in an Indian population, about 73% had a dimple on only one cheek, while roughly 27% had dimples on both sides.3PubMed Central. Evaluation of Prevalence and Morphology of Dimple among Population of Sullia Taluk The dimples also varied in position on the cheek. About 61% sat at the expected anatomical landmark where a horizontal line from the mouth corner intersects a vertical line from the outer eye corner, while the rest appeared at other locations on the cheek.
The fact that a dimple can appear on only one side is another hint that this trait is not governed by a single on-off genetic switch. During fetal development, the two sides of the face develop somewhat independently, and the muscle split that creates a dimple may occur on one side but not the other. This asymmetry is not a sign of anything going wrong. Human faces are not perfectly symmetrical in general, and the zygomaticus major muscle can develop slightly differently on each side without any clinical significance.
Why Dimples Are Not Classified as a Birth Defect
Medical genetics draws clear distinctions between different types of physical variation, and where a feature falls in that classification determines whether it is considered a “defect” at all. The standard framework separates features into three broad categories: common variants, which appear in more than about 4% of the population; minor anomalies, which appear in 4% or fewer; and malformations, which represent actual disruptions in how an organ or structure formed during embryonic development.4PubMed. Phenotypic abnormalities: terminology and classification
Cheek dimples appear in an estimated 20 to 30% of people worldwide. That prevalence puts them squarely in the “common variant” category, well above the threshold for even a minor anomaly. A feature shared by roughly a quarter of the human population is, by definition, a normal variant of human anatomy. Calling it a birth defect would be as misleading as calling blue eyes a birth defect.
Even when minor anomalies are present, they are rarely a medical concern on their own. Isolated minor anomalies, meaning a single unusual feature without any accompanying signs, are unlikely to represent a significant underlying condition.5Nursing for Women’s Health. Physical Assessment of the Newborn: Minor Congenital Anomalies It is only when three or more unusual features cluster together in a newborn that clinicians begin to suspect a broader genetic issue. A baby born with cheek dimples and no other unusual features would never prompt further workup.
The Loaded Language of “Birth Defect”
The phrase “birth defect” itself is increasingly controversial in medical circles. Researchers and patient advocates have pointed out that the word “defect” implies something broken or wrong, which can stigmatize people living with congenital conditions. A global review of terminology used for birth-related differences found that many experts recommend moving away from the term, preferring language like “congenital condition” or “congenital anomaly” instead.6PubMed Central. A review of key terminology and definitions used for birth defects globally
This matters for the dimple question because the framing of the question itself stacks the deck. Asking “are dimples a birth defect?” implies there are only two options: defect or normal trait. In reality, the spectrum of human anatomical variation is enormous, and most of it falls well outside the territory of defects. Dimples are one of many features, like cleft chins, differently shaped earlobes, or variations in finger length, that represent the normal diversity of how human faces and bodies develop. The question is understandable, since dimples are caused by an unusual muscle structure that forms before birth, but the answer is clear: a difference in development is not the same as a defect in development.
Sacral Dimples Are a Different Story
When parents or pediatricians worry about dimples as a potential medical issue, they are usually not talking about cheek dimples. They are talking about sacral dimples, which are small indentations in the skin near the base of the spine, just above the crease of the buttocks. These are common in newborns and are anatomically and genetically unrelated to cheek dimples. They have nothing to do with the zygomaticus major muscle or facial development.
Most sacral dimples are simple and harmless: small, shallow, located on the midline, and close to the anus. These simple sacral dimples are not associated with any underlying spinal abnormality and do not require imaging.7PubMed Central. Sacral dimple: clinical perspectives of lesions hidden beneath the skin A separate study found that a sacral dimple on its own is a poor marker for hidden spinal problems, with no statistically significant link between the presence of a sacral dimple alone and underlying spinal dysraphism.8PubMed. Ultrasound investigation of sacral dimples and other stigmata of spinal dysraphism
The picture changes when a sacral dimple is atypical: unusually large, deep, located off the midline, or accompanied by other skin findings like hair tufts or discoloration. In those cases, the dimple can be a surface marker of an underlying spinal cord issue, and imaging is warranted.7PubMed Central. Sacral dimple: clinical perspectives of lesions hidden beneath the skin Having multiple skin markers near the spine made it about six times more likely that an underlying abnormality was present compared to a single marker alone.8PubMed. Ultrasound investigation of sacral dimples and other stigmata of spinal dysraphism So for sacral dimples, the clinical advice is straightforward: a simple, isolated dimple at the base of the spine is almost always benign, but one that looks unusual or comes with other markers deserves a closer look.
The fact that sacral dimples and cheek dimples share a name leads to confusion. Parents who search “are dimples a birth defect” may be anxious about the small pit they noticed on their newborn’s lower back. If that describes your situation, the reassurance is strong: a simple, midline sacral dimple near the buttock crease is one of the most common findings in newborn exams and almost never signals a problem.
How Cheek Dimples Change Over a Lifetime
Many babies have cheek dimples that later disappear. This is often because infant dimples are caused by pads of baby fat in the cheeks rather than by the bifid muscle structure that creates permanent dimples. As the baby’s face slims and the muscles mature, those temporary dimples fade. Genetically inherited dimples, the ones caused by the split muscle, tend to persist throughout life, though they can become less pronounced with age as the skin loses firmness and the face changes shape. Weight loss can make dimples more visible, while weight gain can sometimes obscure them.
This lifecycle is another reason dimples sometimes get mistakenly lumped in with developmental concerns. A parent notices their infant has dimples, reads that dimples are caused by a “defect” in a muscle, and worries. Then the dimples vanish within a year or two, which only adds to the confusion. In most cases, those early dimples were simply a feature of baby fat, not a sign of any muscular variation at all.
Chin Dimples and Other Facial Indentations
The most commonly discussed dimple is the cheek dimple, but chin dimples (sometimes called cleft chins) are another familiar example. These are caused by a different mechanism: incomplete fusion of the two halves of the jawbone during fetal development, leaving a visible groove in the overlying soft tissue. Like cheek dimples, chin dimples are a normal variant with no medical implications. They tend to follow a dominant inheritance pattern as well, though the genetics are similarly imprecise.
Dimples can also appear in less typical locations, including the corners of the mouth (perioral dimples) and, rarely, on other parts of the body. The common thread is always the same: a localized variation in how underlying muscle, bone, or connective tissue relates to the skin above it. None of these variants affect function, and none require treatment. They are simply expressions of the range of normal human anatomy.
Dimpleplasty and the Cultural Value of Dimples
Far from being viewed as a defect, dimples are widely considered attractive across cultures. They are associated with youthfulness and warmth, and research suggests they can make smiles appear more genuine and engaging. This cultural desirability has created a market for dimple-creation surgery, commonly called dimpleplasty.
Dimpleplasty is a minor outpatient procedure that mimics the natural anatomy of a dimple by creating an attachment between the cheek muscle and the skin. Several techniques exist, including punch excision, suture-based methods, and minimally invasive approaches.9PubMed Central. Dimpleplasty: A Detailed Elucidation-A Narrative Review The procedure typically takes under 30 minutes and is performed under local anesthesia. In one series, most patients were satisfied with their results, though minor complications like swelling and, in a couple of cases, infection were reported.10PubMed Central. Simple Technique for Facial Dimple
Surgeons often place the artificial dimple at a standardized point on the cheek called the KBC point, which corresponds to the intersection of a horizontal line from the corner of the mouth and a vertical line from the outer corner of the eye. But as studies of natural dimple placement show, real dimples do not always sit at that exact spot. About 39% of naturally occurring dimples in one study were located forward of the KBC point, at an average distance of roughly 10 millimeters.3PubMed Central. Evaluation of Prevalence and Morphology of Dimple among Population of Sullia Taluk This means that a cookie-cutter surgical approach can sometimes produce a dimple that looks slightly “off” compared to what nature produces, since facial proportions vary from person to person.
The rise of dimpleplasty is itself a strong cultural argument against the “birth defect” framing. People do not pay for cosmetic surgery to acquire a defect. They pay because dimples are widely seen as appealing. The demand for the procedure has been growing, driven in part by social media and celebrity culture. It is one of the clearest examples of a normal anatomical variation that society actively desires rather than pathologizes.
When Dimples Appear Alongside Other Features
There are rare genetic syndromes in which dimples or dimple-like features appear as one component of a broader pattern of unusual physical findings. In those contexts, the dimple itself is not the concern. It is the combination of the dimple with other features, such as unusual facial proportions, growth differences, or organ anomalies, that leads clinicians to investigate further. This is the same principle that applies to all minor anomalies: one isolated finding is almost never meaningful, but a cluster of three or more prompts evaluation.5Nursing for Women’s Health. Physical Assessment of the Newborn: Minor Congenital Anomalies
If you are a parent who has been told your child has dimples and you are wondering whether to worry, the answer in almost every case is no. Cheek dimples in isolation are simply a charming facial feature with no health implications. Sacral dimples, if simple and midline, are equally benign. The only time a dimple of any kind warrants clinical attention is when it appears alongside multiple other unusual features, and even then, it is the pattern of findings that matters, not the dimple itself.
Why the Genetics Remain Fuzzy
Given how common and culturally prominent dimples are, it is surprising how little rigorous genetic research has been done on them. Most of what we know about their inheritance comes from family pedigree studies and anatomy dissections rather than from molecular genetics. No specific gene or set of genes has been definitively identified as responsible for the bifid zygomaticus major muscle that causes cheek dimples.
This is partly a matter of research priorities. Genetic research funding overwhelmingly targets conditions that affect health, and dimples do not. It is also partly a matter of complexity. Traits that seem simple from the outside, like whether you have a dimple, often turn out to involve interactions among multiple genes and developmental processes that are difficult to untangle. The autosomal dominant label that appears in textbooks and medical literature is a useful approximation, but it glosses over the reality that dimple inheritance does not always follow neat Mendelian patterns. Until someone runs a well-powered genome-wide study specifically targeting dimple formation, the precise genetic architecture will remain an open question. For the practical purposes of a curious parent or a person wondering about their own face, though, the takeaway is simple: dimples run in families, they are common, and they are harmless.