Sigmund Freud speculated that incest and patricide were the only two universal taboos and formed the basis of civilization. However, although cannibalism, in-group murder, and incest are taboo in the majority of societies, exceptions can be found, such as marriages between brothers and sisters in Roman Egypt. Modern Western societies, however, do not condone such relationships. These familial sexual activities are criminalised, even if all parties are consenting adults. Through an analysis of the language surrounding these laws, it can be seen how the policy makers, and society as a whole, find these acts to be immoral.