The etiology of cleft lip and palate is multifactorial and has been associated with genetic determination, teratogenic drugs, nutritional deficiencies, amniotic banding, chemical exposures, maternal hypoxia, and radiation. Most clefts in families are sporadic, however, if 1 parent has a cleft there is a 4-6% chance that their baby will also have a cleft. Interestingly, boys are twice as likely to have a cleft lip (with or without palatal involvement) and girls are more likely to have an isolated cleft palate only.