By Sarina Gomez
Dimples do run in families, so genetics probably plays a part, but nobody has found a dimple gene. The school-textbook rule that “dimples are dominant” has never been backed by a published study. What we do know is how a cheek dimple forms, and that baby dimples often come and go as a child grows.
So if one of you has dimples, your baby might too. Nobody can give you honest odds, and a dimple-free newborn can still grow a pair later.
What actually causes a cheek dimple
A cheek dimple is usually a small quirk in a smile muscle. The main smile muscle, the zygomaticus major, runs from the cheekbone to the corner of the mouth. In some people it splits into two bundles partway down.
Anatomists described this in a 1998 study in Clinical Anatomy of 50 half-face dissections. The double, or bifid, version of the muscle turned up in 17 of the 50 (34%). In several of them, the lower bundle was attached to the skin along its middle. When that person smiles, the muscle tugs the skin inward at that spot, and a dimple appears.
That explains a few things parents notice:
- Dimples show up when smiling, because it’s the muscle pulling, not a permanent dent.
- Some people have one dimple, not two, because the muscle variation can be on one side only.
- Dimples differ in depth, because the attachment and the cheek’s fat over it vary from person to person.
Are dimples dominant? What geneticists actually say
The claim that dimples are a simple dominant trait is repeated everywhere, but the evidence for it is missing. MedlinePlus Genetics, the National Library of Medicine’s genetics guide, puts it carefully: dimples tend to run in families and are “usually considered” dominant, “however, some researchers say that there is no proof that dimples are inherited.” It adds that little research has been done and it’s not known which genes may be involved.
University of Delaware biologist John McDonald went further in his Myths of Human Genetics. He searched the literature and found no scientific papers with genetic evidence on cheek dimples. The dominant-trait rule appears in a 1951 genetics textbook that cited no study for it. Because dimples can appear and disappear over a lifetime, he notes, people can’t even be sorted cleanly into “dimples” and “no dimples,” which a simple one-gene trait would need.
None of this means dimples aren’t inherited. MedlinePlus describes one family where siblings, their father, uncles, grandfather and great-grandfather all had similar dimples in both cheeks. It means the inheritance hasn’t been worked out, so any “50% chance” or “75% chance” you see online is a classroom Punnett square, not a measured number.
If you or your partner have dimples: what you can honestly expect
You can expect a family tendency, not a percentage. Here’s what the evidence supports in each case:
| Your situation | What you can reasonably say |
|---|---|
| Both parents have dimples | Your baby may well have them, but it isn’t certain |
| One parent has dimples | Possible; dimples often show up in some children and not their siblings |
| Neither parent has dimples | Still possible: babies get fat-pad dimples, and dimples can show up from more distant relatives |
| Dimples run through many generations on one side | The strongest hint you can have, and still only a hint |
It also helps to look at your own baby photos. If one of you had dimples as a toddler that faded, or didn’t have them until school age, that tells you how changeable the trait is in your family.
When baby dimples show up, and why they can disappear
Many babies have dimples that come from baby fat rather than the muscle. MedlinePlus Genetics notes that babies are likely to have dimples caused by fat in their cheeks, and that these disappear as the baby fat goes. Other children don’t have dimples at birth and develop them later in childhood. In some people dimples last only until adolescence or young adulthood; in others they stay for life.
In practice, that gives you a rough timeline:
- Newborn weeks. Babies don’t smile socially yet, so you won’t see smile dimples much at all.
- First year. As your baby starts smiling and their cheeks fill out, chubby-cheek dimples can appear, sometimes on one side only.
- Toddler to preschool. Cheeks slim down. Fat-pad dimples may fade, while muscle dimples become clearer.
- School age and later. Some children gain dimples, some lose them, and some keep the same ones for life.
If you’re curious how the rest of the face changes over those years, our guide to how babies’ features change up to age 4 covers the nose, eyes, hair and face shape.
Imagining your baby’s smile with SeeMyBaby
If you’d like to picture who your baby might take after, SeeMyBaby’s parents’ photo portrait takes one photo of each of you and imagines a newborn who blends both faces. One of the questions in the app asks what you’re most curious about, and “nose and smile” is one of the options.
Keep it in proportion: the portrait is an imagined face for fun, not a genetic test. A dimple in the portrait doesn’t mean your baby will have one, and a portrait without dimples doesn’t rule them out. As the research above shows, no one can say that yet.
Sources
- Pessa, J. E. et al. (1998). Double or bifid zygomaticus major muscle: anatomy, incidence, and clinical correlation. Clinical Anatomy, 11(5), 310–313.
- MedlinePlus Genetics, National Library of Medicine. Are facial dimples determined by genetics?
- McDonald, J. H. (2011). Myths of Human Genetics: Cheek dimples. University of Delaware.
For more on which traits pass down and how, see What Will My Baby Look Like?, Do Babies Look More Like Mom or Dad? and the rest of the SeeMyBaby blog.
Questions parents ask
Are dimples genetic from the mother or the father?
Either parent can pass them on as far as anyone knows. No dimple gene has been identified, so there’s no evidence that dimples come specifically from one side.
Can two parents without dimples have a baby with dimples?
Yes. Many babies have dimples from cheek fat, and dimples can also appear in a child when neither parent shows them.
Do baby dimples go away?
Often, yes. Dimples caused by baby fat usually fade as the cheeks slim down, while others appear later in childhood or last for life.
How common are cheek dimples?
There’s no solid population count. The split smile muscle linked to dimples turned up in 17 of 50 half-faces in one anatomy study, which suggests the variation is common.
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