Why do some peoples have dimples?

DIMPLES, particularly on the cheeks, are considered a mark of beauty. Though dimples look lovely, they are in fact a manifestation of a genetic birth defect resulting from a shortened facial muscle. Dimples are caused by a fault in the subcutaneous connective tissue during embryonic development. A variation in the face muscle can also cause dimples.
       Dimples are usually not visible until someone smiles. The smile causes the shorter muscle on the face to get pulled, thus creating a slight depression in the skin which we call dimple. As people grow older facial muscles lose their elasticity and slowly begin to stretch out which is why most old people do not flash a dimpled smile anymore. 
         As dimples are dominant genetics trait just one gene is enough to transfer it from parents to children. Thus even if one parent has dimples, there is a 50 per cent chance of the child inheriting dimples genes.
     Dimples on both cheeks are a common occurrence while a dimple on one cheek is rare.