There is one word that is almost always linked with the urge to run and hide: incest. But what does incest entail and why do some people engage in interfamilial relationships? The origin of incestuous behavior and its ongoing practice remains a puzzle; its beginning is ancient and has been touched on in many religious texts around the world. It doesn’t help that talks about incest, especially in the West, have been tabooed and avoided.

But breaking free from these norms, incest can be discussed objectively. For starters, what is incest? Incest, or consanguineous unions, describes sexual relationships between individuals with at least one common close relative. In legal terminology, incest often includes unions between non-biological and biological relatives. According to a 1995 study by Maddock and Larson, sibling-to-sibling unions appear to be the most common form of consanguineous, or common ancestral, mating. This may still be the case today, but as far as the majority of Western society is concerned, individuals who engage in incest are usually considered sex offenders. Perhaps the lack of public and consensual incestuous relationships leads many people to conclude that all incestuous relationships are forced. So, at least in North America, people inevitably believe that incest is a result of sexual offense or is an offense itself.

If not out of force, or simple malevolent wrongdoing, incest may be a symptom of neurological deficit. Five Torontonian researchers published a 1998 article in the journal Annals of Sex Research containing various studies that found a relationship between brain defects and unusual sexual behaviour. At that time, “the most interesting and best controlled study to date” was a blind study which found that 22 per cent of 86 patients with unusual sexual tendencies demonstrated sexual irregularities associated with specific patterns found in the temporal lobes of the brain. It found that from the sample size of 91 males, 92 per cent of incestuous partners were female and most often, the partner was their biological daughter. In addition, 25 per cent of the incestuous individuals were pedophiles — a particular pattern of brain pathology was found in the left temporal frontal areas of the pedophilic brain.

Like pedophilic offenders, people who initiate incest have at times been referred to in the literature as “incest offenders.” Researchers like Lea Studer and A. Scott Aylwin wonder whether this category should exist on its own. Incest offenders, a subtyping of sexual offenders, seem to have unique statistics that describe them. Like other sexual offenders, incestuous ones seem to have a particular track record that sets them apart. As of now, there isn’t enough information to precisely explain why some people are inclined to partake in incest. It would be interesting to somehow incorporate the concept of “incest avoidance” into the context of research, however. There is undoubtedly an anti-incest attitude that is prevalent in Western society — if you’ve been outside or on the Internet, it’s an idea that finds its way into common insults and is the butt of many jokes. This is pure conjecture, but the sheer resistance to the idea makes you wonder whether or not there are more people out there that have these desires or wishes. But just like with the treatment of other socially defiant behaviours, incest may be something that we train each other to suppress or nip in the bud.

Considering all our norms and values and the studies that show that incest is linked with mental illness, a person may seem a bit off-the-wall to suggest that incestuous thoughts are be a natural part of any family’s relations. But the infamous psychoanalyst Carl Jung explored the incestuous fantasies in families in his book, Psychology of the Unconscious. In it, Jung describes this phenomenon as “kinship libido,” which is necessary in achieving good experiences in early life. “Incest fueled desire” is said to be a part of normal human love that healthy families cannot do without.

On the other hand, this idea, along with the Freudian theory of the Oedipus complex, is contradicted by the Westermarck effect. According to Finnish anthropologist Edward Westermarck, young children raised in close proximity do not sexually imprint on each other or feel any attraction.

It seems that we can generally draw a line between a lingering thought about a stepbrother and actually acting on desires, so what does it take to break that barrier? Maybe you either can or you can’t. Maybe the barrier is best if it is never broken. Discussion about the topic is minimal and cultural resistance, for now, is unyielding.