婴儿中约有千分之一左右是豁唇,因上唇裂开呈三瓣嘴,故俗称兔唇。它是一种先天性畸形,在医学上称为唇裂。为什么生下来的孩子是豁唇呢?有的是遗传性疾病,也就是指上代双亲患唇裂畸形或双亲带有致病基因传给后代。这种畸形在近亲结婚中的发病率比非近亲结婚高三倍,其原因是男女双方带有相同的缺陷基因的机会要多些。所以应禁止近亲结婚。有的豁唇是细胞突变引起的。如父母都没有唇裂畸形,又不是近亲结婚,却生下豁唇的孩子。这是由于妊娠初期,特别是妊娠一至四个月时,患病毒性疾病如风疹、感冒等,或服某种药物如可的松、肾上腺皮质激素、氯喹、苯海拉明、扑尔敏、四环素、灰黄霉素、磺胺增效剂、 About one-thousandth of infants is lip, because the upper lip split three valves, so commonly known as the rabbit lips. It is a congenital malformation, which is medically known as cleft lip. Why is the child born off the lip? Some genetic disease, which means that the previous generation of parents suffering from cleft lip deformities or parents with pathogenic genes passed to offspring. The incidence of this deformity in in-kin marriages is three times higher than in non-kin marriages because there is a greater chance that both men and women have the same defective gene. Therefore, marriage of relatives should be prohibited. Some lips are caused by cell mutations. If parents are not cleft lip deformities, but not married relatives, gave birth to lip children. This is due to early pregnancy, especially during pregnancy one to four months, suffering from viral diseases such as rubella, cold and so on, or taking certain drugs such as cortisone, adrenal cortex hormones, chloroquine, diphenhydramine, chlorpheniramine, Tetracycline, griseofulvin, sulfonamide synergist,