This is an interesting topic to me because of the fact that many (including myself) consider the concept repugnant- but psychology and science can’t properly or completely explain why- and the morality of the matter is complex and often not subject to logic. While morality is subjective and not universal, we won’t explore the nature of morality. Instead let’s ask another question:
“Why is incest immoral at all?”
So there are largely two factors that feed this- sociological factors and genetic factors. Let’s look at generic factors first.
The general stigma is that children born from incest will be somehow abnormal or sick. This isn’t inherently true. What occurs is that generally there are higher chances that both parents will carry certain genetic “defects” or undesirable genes and these genes then have twice the odds and of presenting in offspring as well as a higher potential expression.
With genetic screening however, this issue can be mitigated or eliminated to the point where two properly screened “blood relatives” could have statistically higher odds of having a genetically healthy child than two random non relatives. Now, there is another genetic component that is interesting, and one that may in part explain overall avoidance of incest. Incest would seem to be a good genetic strategy. Asides from social advantages, a child of two siblings may share 70% or more DNA with both parents vs. a child of non close relatives whom generally is closer to 50% genetic matching to either parent. In other words, for a given parent, a child of incest represents a more faithful reproduction of their genes. Over generations of inbreeding, that percentage can increase to where children are almost clones of their parents. If two parents had “perfect” genes to where undesirable gene pairs weren’t passed down or subsequent pairings were selected to avoid this issue- the concern…
.. of defects is essentially a non issue. So what is the problem? Well… bacteria and parasites. Micro organisms that prey on humans tend to love short lives. That is why viruses and such evolve so quickly and can outpace the immune systems and defenses of macro organisms. In a single human lifetime there can be millions or billions or more generations of offspring for a virus. So the sort of drastic evolution seen between a dinosaur fossil and a bird, for a virus it can evolve the equivalent of that in the time between your birth and funeral perhaps.
Meaning that as a parasite becomes skilled at attacking the parent, a child with such genetic similarity would not be hard to adjust to. The virus has a huge head start and can quickly outpace the immune systems of subsequent children. It is theorized that diversity in genetic mates helps lead to longer lives and healthier populations because that genetic diversity helps combat parasites from becomes too specialized in a hosts genetics.
But- what if the partners use protection or are infertile? What then is the genetic reasoning for the aversion to incest? At that point there isn’t really any and that leads us to social and cultural factors.
A major factor here is power or influence. That is to say that a strong argument against incest is that especially between an authority figure like a parent and child etc. but even between perhaps a “role model” like an older and younger sibling, there is an abuse of power. Traditionally speaking and especially where social welfare and/pr opportunity and means of self sufficiency are lacking, the figures of authority in a home have disproportionate power over those within the home. “My house, my rules.” There are implicit and explicit ways that power or a “pressure” are used in normal interactions seen as innocuous. Curfews and dress codes, expectations on grades or employment, rules in dating or who is allowed at the home and when etc etc.
In an environment where it is considered acceptable for family members to engage in romantic relations with each other though, there are many ways power or trust can be abused and consent becomes a real issue. There are quite a few other social reasons against the practice- but it gets interesting when we start examining them. For example, in many cultures including common cultures in the west such as “rural” communities, the community often exists as an extended family of sorts. While these people often have no meaningful blood relation, they are in effect extended families with many of the same ethical questions of control and trust and access as within nuclear family units. This can especially be seen as an ethical quandary in cultures that have some form of “arranged marriage” in which members of a community which functions as an extended family use their access and power over their own blood relatives to force or coerce or instigate romantic pairings.
That is to say- if we take two genetically distinct families that share close social or communal ties and are acting in a sense that marriage “combines” or “joins” families as one- if family A and family B make a formal arrangement (forced marriage) or informal arrangement (gee- we should encourage and raise our kids to grow up and get married…), for Daughter A and Son B, this could be argued to ethically be no better than incest in the sense that we still have issues of undue influence or pressures shaping the choice of partners. We are still operating with the genetic component removed, but that doesn’t clear up the social ethics.
To be clear I am NOT here to say that any sort of “arranged marriage” is wrong or is akin to incest- I am saying that the ethical challenges bear striking similarity but we often do not view the issues the same and that when we focus on the ethics of arranged marriage most people concentrate on ideas concerning personal freedoms but to the contrary incest is generally not viewed in the lens of personal freedom.
Like I said- it’s all rather interesting. For whatever the reason(s) across much of time and many cultures and even just intuitively- incest creeps a good majority of us out. Explaining why and being able to logically reconcile that are not completely explored yet. Many theories and guesses, few answers.
I suppose I’ll close up with this interesting one that psychologists are working to explain. Ok- whatever the reason is- most people seem to naturally be averse to incest. While studies suggest that there is some mechanism that makes us see people we grow up as “family” with from a young age as not perspective sexual partners there are some inconsistencies and twists there, but even if we take it at face value there’s just something inside most people that makes us not want to have sex with family members…
Why do so many people feel disgusted or outraged at the concept of OTHERS involved in incest? Logically and demonstratively we know that our own feelings of morality or lack of desire do not require us to have such feelings towards others. You can hate eating spinach without being disgusted by others eating spinach. You can feel like it is cheating to read strategy guides for a game without thinking poorly if others who do. So why is it almost universal that we humans extend our…
.. disgust on this topic to others..? Several theories have been proposed and a recent study suggests that there is some correlation between our response to the concept of incest not involving us or our own kin that relates to the duration of time a person was raised when young with a close family member or one considered as family of the opposite sex. There is still no definitive answer in this one either, and the question of why some people or many people feel offense towards others not following their personal morals in matters which do not involve that person at all is a larger question. But yeah. It’s a complex subject that is full of potential insights and all manner of uncomfortable twists.
“Why is incest immoral at all?”
So there are largely two factors that feed this- sociological factors and genetic factors. Let’s look at generic factors first.
The general stigma is that children born from incest will be somehow abnormal or sick. This isn’t inherently true. What occurs is that generally there are higher chances that both parents will carry certain genetic “defects” or undesirable genes and these genes then have twice the odds and of presenting in offspring as well as a higher potential expression.
Meaning that as a parasite becomes skilled at attacking the parent, a child with such genetic similarity would not be hard to adjust to. The virus has a huge head start and can quickly outpace the immune systems of subsequent children. It is theorized that diversity in genetic mates helps lead to longer lives and healthier populations because that genetic diversity helps combat parasites from becomes too specialized in a hosts genetics.
A major factor here is power or influence. That is to say that a strong argument against incest is that especially between an authority figure like a parent and child etc. but even between perhaps a “role model” like an older and younger sibling, there is an abuse of power. Traditionally speaking and especially where social welfare and/pr opportunity and means of self sufficiency are lacking, the figures of authority in a home have disproportionate power over those within the home. “My house, my rules.” There are implicit and explicit ways that power or a “pressure” are used in normal interactions seen as innocuous. Curfews and dress codes, expectations on grades or employment, rules in dating or who is allowed at the home and when etc etc.
Like I said- it’s all rather interesting. For whatever the reason(s) across much of time and many cultures and even just intuitively- incest creeps a good majority of us out. Explaining why and being able to logically reconcile that are not completely explored yet. Many theories and guesses, few answers.
Why do so many people feel disgusted or outraged at the concept of OTHERS involved in incest? Logically and demonstratively we know that our own feelings of morality or lack of desire do not require us to have such feelings towards others. You can hate eating spinach without being disgusted by others eating spinach. You can feel like it is cheating to read strategy guides for a game without thinking poorly if others who do. So why is it almost universal that we humans extend our…