I don’t watch much television but I do enjoy the HBO series Game of Thrones . In anticipation of the final season, which starts next month, I’ve been re-watching all the episodes from seasons one to seven. I am sure I’m not alone in this. Among the many narratives of the show is one that depicts the incestuous relationship between a pair of high-born fraternal twins. Incest is a long-standing taboo in human society. So repugnant is the idea of sexual relations between closely related kin that in many societies, even those where individual freedoms are sacrosanct, incest between two consenting adults is illegal, regardless of whetherthe union results in any offspring. In Canada, for example, sex between adult siblings, between parents and their grown-up children, and between grandparents and their adult grandchildren is a crime punishable by imprisonment. Incest between grown-ups and children, or perpetrated on a non-consenting adult, is rightfully criminal and should remain so. Incest was not unknown in the ancient world. If we take the Bible’s creation myth literally, then the whole human race is a product of incest, for how else could Adam and Eve, in the absence of external agencies, have populated the world? The biblical patriarch Abraham’s wife Sarah was his half-sister (or niece according to another interpretation), and the parents of Moses were nephew and aunt, or cousins, again depending on which version you choose to believe. The royal families of ancient Egyptian dynasties were famous for wedding brothers and sisters to “keep the line pure”, a historical fact that no doubt informed the predilection for incest in one of the fictional royal houses in Game of Thrones . Incest, necrophilia and other sexual offence laws in Hong Kong need updating The Chinese established a highly rigid clan and familial structure early on in their history, and incest was the antithesis to the framework that governed kinship, and by extension, human society. Their very word for incest, luanlun , literally means “to bring disorder to normal human relationships”, and throughout the nation’s history it was condemned as a monstrous crime. Among the recorded occurrences of incest, the most outrageous was that committed by emperors Xiaowu and Qianfei of the Liu Song dynasty, in the 5th century. Although Emperor Xiaowu was considered a competent ruler during the decade of his reign, he engaged in incest not only with his first cousins, but more repulsively, with his own mother Empress Dowager Lu. After he died in 464, his son Emperor Qianfei followed his father’s incestuous ways by bedding his aunt and his elder sister. Lacking his father’s ability, however, the 17-year-old Qianfei was murdered after less than two years on the throne. While having sexual relations with one’s parents, siblings, aunts and uncles was roundly condemned, the Chinese had a curious notion about first cousins marrying. According to rules that were based more on artificial patrilineal conventions than on genetic reality, first cousins who shared the same surname (that is, the children of one’s father’s brothers) could not marry, but no such prohibition existed for first cousins who didn’t share a common surname (the children of one’s father’s sisters and one’s mother’s siblings). The first cousins Emperor Xiaowu bedded were the former. The main conceit of the famous novel Dream of the Red Chamber (1791) is protagonist Jia Baoyu’s love for his first cousins – Lin Daiyu, daughter of his father’s sister, and Xue Baochai, daughter of his mother’s sister – and his struggle to choose between them. Realising that first cousins, with or without a shared surname, have the same level of consanguinity, and hence the same risk of genetic disorders associated with inbreeding, such unions are now illegal. These laws, however, assume procreation. If there are no children, then it becomes a victimless crime that doesn’t offend a society that is no stranger to first cousin marriages throughout its history.