There are many causes of cleft lip and palate. Problems with genes passed down from 1 or both parents, drugs, viruses, or other toxins can all cause these birth defects. Cleft lip and palate may occur along with other syndromes or birth defects. The causes of orofacial clefts among most infants are unknown. ... Cleft lip and cleft palate are thought to becaused by a combination of genes and other factors, such as things the mother comes in contact with in her environment, or what the mother eats or drinks, or certain medications she usesduring pregnancy. Deficiency of B vitamins and folic acid in maternal diet is another commonly associated cause of cleft lip and palatein the new born. Parents who are older than usual at the time of birth of their baby are at higher risk of having children with cleft lip and or palate.