- "True, we don't tie ourselves in knots over a discreet bit of buggery, but... brothers and sisters? Where I come from, that stain would be very difficult to wash out."
- ―Olenna Tyrell to Tywin Lannister
Incest is the act of engaging in sexual intercourse with one's direct family member (siblings, parents, offspring). It is a great cultural taboo both in the Seven Kingdoms and the lands beyond the Wall.
Intermarriage between first cousins is actually not considered "incest" in Westerosi society. A prominent example is that Tywin Lannister married his own first cousin Joanna Lannister, mother of all three of his children.
Alongside kinslaying and the violation of guest right, incest is proscribed by every major religion in Westeros. Children born of incest are deemed abominations.
Children born of incest tend to have imperfections in both body and mind. One major example are the Targaryens, whose members are infamous for going insane as a result of centuries of inbreeding.
Strangely enough, members of House Blackgard who are born from incest, tend to grow taller and age older than the rest of their relatives. Two major examples are Lords Arthur and Trevyr Blackgard. Arthur, who reportedly was born from an incestuous relationship, aged to 112. Trevyr, whose parents were first cousins to each other, also aged to be 90 and was about 198 cm tall. This is quite rare, since highborn bordermen over the age of 80 are a rarity.
Known instances of incest[]
- The members of House Targaryen, like their ancestors of the Valyrian Freehold, often married brother to sister to keep their bloodline pure. However, generations of such heavy inbreeding increasingly produced insanity in some of them. After three centuries of this, varying forms of insanity became so common in the family that it was said that every time a new Targaryen was born, the Gods would flip a coin to determine if it would grow to be insane. This caused the Targaryens some problems with the Faith of the Seven, which proscribes incest, but due to the power of the royal family the Faith turned a blind eye towards them.
- In the current generation, King Aerys II Targaryen, the Mad King, married his own sister, Queen Rhaella Targaryen. Their three children, Rhaegar, Viserys, and Daenerys, are thus all the products of incest (and thus not only siblings but first cousins to each other). This heavy inbreeding made King Aerys fall into insanity as he grew older, and Viserys was showing signs of being quite unstable as well. Rhaegar and Daenerys apparently avoided any ill-effects from their incestuous bloodlines, however the Targaryen madness has been known to appear later in life.
- Although Rhaegar's wife Elia Martell wasn't a direct family member, she was a distant cousin of the Targaryen line due to her ancestor Prince Maron Martell marrying the sister} of King Daeron II Targaryen (Rhaegar's great-great-grandfather) who had likewise married Maron's sister, making Rhaegar a distant cousin to House Martell. When the Targaryens had no sisters to marry, they would often at least try to marry cousins to keep the bloodline as "pure" as possible.
- Queen Cersei and her twin brother Ser Jaime Lannister have continued an illicit romance since childhood. Cersei's children: Joffrey, Myrcella, and Tommen, are all born of their affair. Similar to the Targaryens, this incestuous bloodline has apparently produced severe mental health defects in Joffrey. While he did not hear voices or see hallucinations of things that aren't real, Joffrey was a sadistic, cruel, and short-tempered sociopath. Cersei and her younger brother Tyrion explicitly discuss how the Targaryens experienced similar mental and behavioral problems after generations of incestuous inbreeding. Myrcella and Tommen, however, beat the odds and possess no (biological) mental health problems.
- Tywin Lannister married his own first cousin Joanna Lannister, though this is not considered "incest" in Westerosi culture. This does make their children Jaime, Cersei, and Tyrion not only siblings, but second cousins to each other. Technically, this also makes Joffrey, Myrcella, and Tommen not only siblings and first cousins, but third cousins as well.
- The wildling Craster takes his daughters as wives and does the same on the daughters he sires on them, such as Gilly.
- Theon Greyjoy, albeit unknowingly, attempts to seduce his own sister Yara before recognizing her, and begins touching her as they ride for Pyke. She knew, but let him do it so she could later reveal her identity and humiliate him about it.
- Trovar Blackgard married Aurola Blackgard, his first cousin, though this is not considered incest in bordermen culture. This makes their two sons Asterion and Trevyr Blackgard brothers, but also second cousins.
- Emeric Blackgard and Jeyne Heartley, who were half-siblings, were engaged in a romance during their teenage years; not knowing they were related. This was due to the fact that Emeric could no longer remember who his maternal family, House Heartley, was. Emeric's father, Steffon Blackgard, never told him of his mother's identity and Meryanne Heartley, Emeric and Jeyne's mother, did not recognize her son. Jeyne died not knowing her lover's heritage, while Emeric eventually discovered Jeyne's real name just after she died, partly influencing his decision to leave Westeros for Essos.