The taboo is not only social but legislative; 24 states ban the marriage of first cousins: five others allow it only if the couple is unable to bear children.

• 这种禁忌不仅是社会习俗方面的，而且有来自立法机关的：有24个州禁止近亲结婚；其他5个州只有在一对夫妻不育的条件下才许可。