Cleft lip and palate occurs in approximately 1 in 1000 births, while isolated cleft palate occurs in 1 in 2500 births. Cleft lip and palate is twice as common in male children, whereas isolated cleft palate is twice as prevalent in female children. This gender difference arises because the fusion of mesodermal processes within the mouth during the embryonic period occurs approximately one week later in female babies; failure of these processes to fuse leads to the formation of a cleft palate. Geographically and ethnically, cleft lip and palate is observed more frequently in East Asian populations, while it is less common among African Americans. No significant difference is observed between ethnic groups for isolated cleft palate.