I. What are the causes of cleft lip and palate? The root cause of cleft lip and palate is not yet known with certainty, but there are usually two major causes: (a) Environmental factors: The following conditions in the early stages of pregnancy (before the third month of pregnancy) may cause cleft lip and palate in the baby: (1) Viral infections: such as upper respiratory tract infections in pregnant women, rubella, etc. 2, drug effects: such as taking anti-epileptic drugs, cholesterol-like, anti-allergy, anti-cancer drugs, etc. 3, endocrine: mental or injury factors, such as being subjected to strong mental stimulation, external body damage, etc. 4, nutritional factors: early pregnancy vomiting, anorexia, paranoia, etc., resulting in vitamin D, folic acid, iron, calcium and other deficiencies. 5. Other factors: such as exposure to X-rays, smoking, alcoholism, lack of oxygen. (B) Genetic factors: A significant portion of cleft lip and palate is hereditary, and the incidence of the disease in the offspring of those with cleft lip in the immediate family is about 4%. The general probability of cleft lip and palate occurring in the first child is 1/600, and if the first child has a cleft lip and palate the chance of cleft lip and palate occurring in the second child is 3/100. II. Can cleft lip and palate be inherited? Cleft lip and palate is a disease caused by many factors. Genetics is only one of the causes. The mother’s exposure to radiation during pregnancy, previous medication, viral or other diseases such as flu and rubella in the first trimester, and poor nutrition in the early stages of pregnancy may lead to the formation of cleft lip and palate in the fetus. If the father or mother has cleft lip, the chances of the child having cleft lip are higher than the general population because cleft lip itself is genetically predisposed. However, the chance of inheritance is very low. When is the best time for cleft lip and palate surgery? For cleft lip and palate patients, in principle, the earlier the treatment, the better. Cleft lip surgery can be performed as early as 24 hours after birth or 3 months after birth if the patient’s immunity is sound, because not only is the baby’s immunity strong enough to tolerate infection, but also the tissue cells of the body are very naive at this time, so it is not easy to form scars, creating good conditions for postoperative deformity recovery; cleft palate surgery should be performed after the baby is born for 6 months at the earliest.