What causes clefting?
The exact cause is unknown. Cleft lips and cleft palates are congenital defects that occur early in embryonic development. Scientists believe a combination of genetic and environmental factors, such as maternal illness, drugs or malnutrition, may lead to a cleft lip or cleft palate. If one child in a family is born with a cleft, the risk increases by 2 to 4 percent that future children in the family will suffer from the same defect.
