Funnel chest is the most common congenital chest wall deformity, with a male to female ratio of 4:1 and an incidence of 38/1,000 in Caucasians, 7/1,000 in Blacks, and 20/1,000 in other races. Ninety percent of cases are congenital, and it is not clear whether genetic factors are involved in the pathogenesis, but it has been reported that family members of patients with funnel chest often suffer from either mild or severe chest wall deformities. Twins and several generations of the same family have also been reported to have the disease. Many members of these families are actually carriers of connective tissue disease, suggesting that their pathogenesis may be due to the lack of a particular connective tissue gene, but the mode of inheritance is not known and the main genes involved in the development of funnel chest are not yet known. Ethnic predisposition is also unclear, but it appears to be significantly more prevalent in Caucasians. In a large survey of patients with idiopathic funnel chest conducted in a large teaching hospital in the United States, 89% were Caucasian, 9% were Hispanic, and 2% were Asian. Whether this reflects interracial genetic differences or different racial predispositions is not known. No large epidemiological studies have been reported in Asia or China.