Taboo Biological Cost – Genetic Mutations Resulting from Incest

  • Incest Taboo Meaning
  • Incest Family Taboo
  • Incest Genetic Disorders
  • Incest Genetic Mutation

Taboo Biological Cost – Genetic Mutations Resulting from Incest
Taboo Biological Cost – Genetic Mutations Resulting from Incest

Genetic mutations are the biological cost of the taboo that is incest

Incest has been and still is a taboo in almost every culture around the world. History, however, provides ample evidence of incestuous relationships that prevailed in several countries many centuries ago. Royals and nobles in some nations kept royal blood pure by marrying blood relatives.

Incest /ˈɪnsɛst/ is sexual activity between family members or close relatives.[1][2] This typically includes sexual activity between people in a consanguineous relationship (blood relations), and sometimes those related by affinitystepfamily, those related by adoption or marriage, or members of the same clanor lineage.

Egyptian rulers would marry their siblings or their biological children because they believed in incest. Yet the fact remains, incest has genetic implications and could give rise to grave genetic mutations. History provides numerous cases to prove this.



There are subjects of morality that guide human nature on various levels. One rule of nature that guides human behavior says not to have sex with first-degree relatives.

First-degree relatives are people who share 50 percent of your genes. They include parents, siblings, and offspring. Humans are socially and psychologically tuned to abhor the concept of incest. In fact, almost all cultures forbid marriages between first degree relatives.

Psychologist Jonathan Haidt found that the thought of engaging in sexual acts with first-degree relatives is very repulsive for most people.


Genetic Mutations Resulting from Incest
Genetic Mutations Resulting from Incest


The Biological Cost of Incest

Anti-incest mechanisms are widespread across human societies because sex between first-degree relatives can lead to genetic defects in their offspring. Interbreeding between close relatives poses problems involving recessive traits.

Any recessive defect in one partner is passed on to their offspring because their genetic structures are too similar. Incest can cause genetic abnormalities to express in the offspring, giving rise to genetic mutations.

Four studies of incest between first-degree relatives revealed that forty percent of children were born with genetic disorders. These genetic disorders included congenital physical malformations, intellectual deficits or autosomal recessive disorders. 14 percent of such children were born with slight mental disabilities.

Thus, the odds of a child suffering an early death or congenital disability and mental disability is somewhere close to 50 percent.


Genetic Mutations Resulting from Incest
Genetic Mutations Resulting from Incest

Genetic Mutations resulting from Incest

There are a few genetic mutations that result from incest between first degree relatives. These are as follows:

The Habsburg jaw

This genetic condition is also known as prognathism. The House of Habsburg, who ruled between 1400 and 1700 B.C. inspired the name. The royal family resorted to interbreeding for protecting their interests. As a result, their children were born with jutting, long lower jaws with grave under-bites. Even today, members of the Habsburg family show mild variations of prognathism, thus reflecting its long-lasting effect.

Elongated skulls

Some Egyptian sculptures have elongated heads. This was not an artistic choice but a reflection of a genetic mutation that prevailed during the era. Egyptian royal families produced offspring with deformed skulls as they relied on incest. For instance, King Tut suffered from skull deformation, a cleft palate, club foot and scoliosis.


Genetic Mutations Resulting from Incest
Genetic Mutations Resulting from Incest


Cleft palate

Cleft palate occurs when the roof of the mouth is malformed. King Tut, who was a product of incest, suffered from a cleft palate and faced troubles while eating, breathing and speaking. India and Kenya have ample cases of incest-related cleft palates. Moreover, poor genetic diversity and impoverishment are allegedly the cause of cleft palate in several parts of Kenya.


Some European royal families depended on incest. When Queen Victoria and Albert had a child, they noticed he had troubles with blood clotting. Although this child wasn’t a result of incest between siblings, their offspring showed the same problem down the line. This issue, hemophilia, is sometimes called “the royal disease”. Their descendants were carriers of this genetic disorder, which made blood clotting difficult and led to infections and death.




Microcephaly is a condition where a child is born with a small head. This condition is particularly common in Pakistan because Pakistani Muslims marry within the family. Microcephaly often means an under-developed brain, which causes slight to severe mental disabilities. 1 in 10,000 Pakistanis has microcephaly because incest is still prevalent in Pakistan.


Malformed or misshapen bones define clubfoot in the foot. Incest between first-degree relatives can lead to this. Clubfoot is present at birth and affects either one foot or both feet. In most cases, both feet are affected. The condition also becomes more severe after many generations of incestuous associations. Clubfoot can impair the child’s ability to walk and often calls for surgery. King Tut was one of the royal sufferers of club foot as a result of incest.


Dwarfism is a condition that stunts growth and poses heart-related issues in sufferers. Generations of incestuous relationships often lead to dwarfism in the offspring. Although sometimes a hormonal condition, dwarfism can be attributed to incestuous mating between genetically similar individuals. Lancaster, a small settlement in Pennsylvania, had issues with inbreeding in the 1700s. They experienced high infant mortality rates and infertility and saw the emergence of Ellis-van Creveld disease, a condition associated with dwarfism.




More often than not, genetic conditions lead to albinism. It is an autosomal recessive disease occurring because of interbreeding between genetically similar individuals. Lack of melanin in eyes, hair, and skin is the key features of albinism. Puerto Rico has a lack of genetic diversity, which makes it the largest region with albinism in the world.

Immune system disorder

Children of incestuous mating suffer from malformations in muscles, skeleton, and organs. The immune system of such children lacks the alleles for fighting different diseases. Their body loses its ability to fight infections or repair cells. Hence, they fall sick very often. Immune system disorder is another incest-related problem faced by genetically-compact countries.


Cryptorchidism occurs when one or both testes in males fail to descend into the scrotum. Approximately 3% of male babies are born with this condition. Cryptorchidism causes infertility and other sexual health issues in boys. The condition is often a result of duplicated chromosomes and incestuous relationships.