Microtia, in this context, refers to congenital malformations of the outer and middle ear. It usually presents as a malformation of the auricle, with narrowing or atresia of the external auditory canal, together with malformations of the middle ear structures and occasionally of the inner ear. Only a small percentage of children with small ears have a simple auricular deformity; most children with small ears, especially those with significant auricular deformities, will have malformations of the outer and middle ear structures. In other words, outer and middle ear deformities often coexist. How many children in the country, too, have small ears? According to a survey conducted in 1992, the prevalence of microtia in China is between 1 and 1.4 per 10,000, and it is estimated that about 130,000 people in China have microtia. Of these 130,000 people, about 97,500 are unilateral microtia and 32,500 are bilateral microtia. I have also noticed in my clinic that there are more children with small ears on the right side than on the left side, which is also consistent with the results of large-scale surveys. The cause of microtia is still unclear. However, the literature and clinical practice suggest that it may be related to the following factors: 1. Genetic factors. Some populations have developed obvious or severe multiple malformations, then the likelihood of their next generation developing malformations is high. The same is true for small ears; 2. Environmental pollution. Toxic substances in the environment may cause abnormal development of the fetus and eventually malformations.