Final answer:
The incest taboo is a cultural norm against sexual relations with close kin, found in nearly every society. Its definition differs globally, but it typically includes immediate family and sometimes extends to other relatives.
Step-by-step explanation:
The question of whether the incest taboo is universal has a nuanced answer. It is true that a form of incest taboo is indeed found in virtually every society. However, the definition of what constitutes incest can vary widely among different cultures. For example, while sexual relations between parents and their offspring are almost universally prohibited, there are variations when it comes to cousins or relatives from certain sides of a family. Moreover, sociological studies have shown that social norms, including those surrounding sexuality, can highly differ from one society to another. Interestingly, what remains consistent is the presence of an incest taboo, signaling an almost universal cultural norm against sexual relations with close kin.