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Genetics of cheek dimples
Summary
You might have dimples in one or both of your cheeks when you smile, and you may have heard that dimples are determined by a dominant allele. As far as I know, no one has done family studies to test this, but it seems unlikely to be true. Don't worry if your family includes two parents without dimples and a child with dimples, and if you're a teacher, don't use dimples as an example of a simple genetic trait.
Are there just two kinds of cheeks?
Some people have barely noticeable dimples, while people have deep, obvious dimples. Wiedemann (1990) suggests that the appearance of dimples may be affected by circulation, body weight or muscle tone, although he does not cite any evidence for this. He describes several individuals who had dimples as children and lost them by adulthood. All this means that dividing people into two distinct types, having dimples vs. not having dimples, is pretty arbitrary.
One of the many muscles in your face is the zygomaticus major muscle; it goes from your cheekbone to the corner of your mouth, and pulls up the edge of your mouth when you smile. Pessa et al. (1998) dissected 50 cadavers and found that the zygomaticus major muscle was split into two muscle bundles in 17 of them. They speculated that a split zygomaticus major muscle may be the cause of dimples. Phan and Onggo (2019) reviewed several studies, with a total of 259 cadavers, and found that overall, 23% of cadavers had a split zygomaticus muscle. I don't know if anyone knows which cadavers had dimples when they were alive and smiling, so it's not clear whether a split zygomaticus muscle is really the cause of dimples.
Family studies
Winchester (1951), in his widely used textbook on genetics, said that dimples are inherited "apparently as a dominant, but with some variation in expressivity." I don't know where he got this idea, because I haven't been able to find any published studies on the genetics of dimples from before 1951. I haven't found any family studies of the genetics of dimples from after 1951, either.
Genome data
23andMe says that by comparing the DNA of customers who report that they do vs. do not have dimples, they have identified 9 different genetic variants that are associated with dimples. Unfortunately, they haven't published their results.
Further research
While it might be kind of fun to see which genes 23andMe found that have some influence on dimples, I can't think of a reason to do more genetic research on the trait. It might be interesting to see if dimples really are caused by a split zygomaticus major muscle, maybe by using ultrasound on living people instead of dissecting cadavers.
References
Pessa, J.E., V.P. Zadoo, P.A. Garza, E.K. Adrian, A.I. Dewitt, and J.R. Garza. 1998. Double or bifid zygomaticus major muscle: anatomy, incidence, and clinical correlation. Clinical Anatomy 11: 310-313.
Phan, K., and Onggo, J. 2019. Prevalence of bifid zygomaticus major muscle. Journal of Craniofacial Surgery 30: 758-760.
Wiedemann, H-R. 1990. Cheek dimples. American Journal of Medical Genetics 36: 376.
Winchester, A. M. 1951. Genetics: A survey of the principles of heredity. Houghton Mifflin Company, Cambridge, Massachusetts.
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This page was last revised October 26, 2026. ©2026 by John H. McDonald. Content is available under the Creative Commons Attribution-Noncommercial license.