It is a condition in which there is an openings or splits in the upper lips, the roof of the mouth or both. It is a form of oral malformation and usually it occurs during the early pregnancy.

Cleft lip, with or without cleft palate, affects one in 700 babies annually, and is the fourth most common birth defect in the U.S. Clefts occur more often in children of Asian, Latino, or Native American descent. Compared with girls, twice as many boys have a cleft lip, both with and without a cleft palate. However, compared with boys, twice as many girls have cleft palate without a cleft lip.

The causes of cleft lip and palate is still unknown, the scientist believes that genetic and environment are some of the factors, like the medications that the mother takes during the pregnancy. The scientist says that this physical disorder couldn't be prevented.