Predict the probability of your baby having a cleft chin (mentum bipartitum) based on parental status and family history, using dominant inheritance with variable penetrance.
Fill in the fields and press Calculate. Grandparent inputs are optional but improve accuracy.
Generated at traitgen.com. Free genetics education. Not medical advice.
Fill in the form and press Calculate to see your result here.
⚠️ Educational only. Probability estimates based on genetic models, not medical advice.
Despite being called a dimple in many languages, a cleft chin is actually caused by incomplete fusion of the two halves of the chin bone (mandible) during fetal development. It is more anatomically similar to a skull feature than a skin feature. Famous individuals with cleft chins include Cary Grant and John Travolta.
A cleft chin (mentum bipartitum) is caused by incomplete fusion of the two halves of the chin bone (mandible) during fetal development, leaving a visible groove or dimple. Like dimples, it is generally considered a dominant trait with incomplete penetrance, influenced by multiple genes in the chin development pathway.
The mandible forms from two separate embryonic processes that fuse at the midline. In people with cleft chins, this fusion is incomplete, leaving a groove of varying depth. The degree of fusion is controlled by genes regulating midline facial development, making cleft chin more of a spectrum than a binary trait.
Cleft chin is transmitted as a dominant trait: one copy of the relevant variant is typically sufficient to produce some expression of the cleft. However, expression varies from a dramatic deep groove to a very subtle dimple. Some carriers show almost no visible cleft, particularly when facial fat fills in the groove during childhood. The trait often becomes more prominent in adulthood as subcutaneous fat redistributes.
Cleft chins are approximately twice as common in men as in women even within the same family. This is because testosterone promotes a more prominent, angular chin during puberty, which makes the underlying groove more visible. Oestrogen tends to produce softer, rounder chin contours that can mask a mild cleft. A girl carrying the cleft chin gene may show only a subtle indentation compared to her brother with the same genetics.
A true cleft chin involves a groove in the chin bone itself. A chin dimple is a skin-level indentation without bone involvement. These are distinct traits with different developmental origins, though they can look similar and are sometimes confused. Cleft chin is more heritable and more consistently expressed than soft-tissue chin dimples.
It is unlikely but possible. If both parents carry a silenced or low-penetrance cleft chin variant, a child could inherit a combination that expresses more strongly. Alternatively, spontaneous developmental variation in mandible fusion can rarely produce a mild cleft. The probability is low, around 5 to 8 percent, but increases if grandparents on either side have cleft chins, indicating possible carrier status in the parents.
Not exactly. A cleft chin involves a groove in the underlying chin bone (mandible) caused by incomplete midline fusion during fetal development. A chin dimple is a soft-tissue indentation without bone involvement, similar to cheek dimples. They look similar but arise from different developmental processes. Cleft chins are more heritable and more consistently passed through families than soft-tissue chin dimples.
No. A cleft chin is a cosmetic variant with no functional health implications. It does not affect jaw strength, dental health, speech, or any biological function. It results simply from the degree of midline fusion of the mandible during fetal development, a structural variation without medical significance.
Cleft chins appear more prominent in men because testosterone during puberty promotes a more angular, prominent chin shape, making any underlying groove more visible. The same genetic variant that produces a subtle dimple in a woman may create a deep, clearly defined cleft in her brother or son because the male hormonal environment amplifies the structural expression of the trait.