Despite scientific advancements that can eliminate all birth defects, why would incest still be a taboo?

Question

First and foremost: do we all agree that the main reason that incest or inbreeding is bad is because it leads to the passing down of recessive genes and these birth defects can severely impact the lives and growth of its offspring in some cases?
Suppose science can do something about it and correct those recessive genes so that, biologically speaking, it is no longer a valid excuse to ban incest.

I actually had no idea how to convince all religious groups to accept incest, but let's suppose I managed to get them on board by hook or by crook. I suspected that science and religion are still the biggest drivers in our present day society since they greatly shaped our culture and affect how policies are laid out, so now I can safely say I have the official green light from science, religion, law and politics to lift the ban on incest.

In that case: why is incest still considered a taboo?

Answer 1

Because it breaks down the distinction between familial love and romantic love, concepts which many people would rather have separated for many reasons. Wikipedia said it better than I could:

In most societies, it is within families that children acquire socialization for life outside the family, and acts as the primary source of attachment, nurturing, and socialization for humans. Additionally, as the basic unit for meeting the basic needs of its members, it provides a sense of boundaries for performing tasks in a safe environment, ideally builds a person into a functional adult, transmits culture, and ensures continuity of humankind with precedents of knowledge.

What happens when it stops solely being about those things? What happens when the parents do things other than "building people into functional adults" - for instance, grooming their children into "ideal" romantic partners? Hell, it might even happen subconsciously, which is why people fear it; they want strong taboos drilled into themselves so that their minds don't...slip.

On top of that, people might be concerned that the distinction between platonic (i.e. friends) love and romantic love is next.

Without several accompanying fundamental alterations in human nature, this is a bad idea in the minds of many.

Answer 2

Diversity:

Just because a double recessive trait isn't a lethal or results in a grossly dysfunctional disease doesn't mean that having hundreds of people who are essentially identical is a good idea. Inbreeding results in a lack of genetic diversity, setting up a situation where a population can be wiped out by a single disease, or a single way of thinking results in the same mistakes being made over and over.

By outbreeding (both in genes and in how things are done) a group has multiple options to deal with a changing environment. Just as a population consisting entirely of clones is a recipe for ultimate disaster, a population with low diversity is weaker and less resilient in the face of changing conditions.

Answer 3

Because it's hard-wired into the brain at some fundamental level. Taboos are like that... they're not things that people think about carefully, and after careful study then they become disgusted.

Instead, it is a profound reaction guided by brain structures written into our genetic code.

It's possible that evolution would eventually weed out this taboo predisposition, supposing that there were evolutionary pressure and a few million years to do so. Even then, what possible evolutionary pressure could make such happen? You'd need ongoing survival threats that unequally discriminated against those with strong taboo sentiment over many generations.

I can't imagine any plausible scenarios.

Answer 4

Because avoiding incest is a biological imperative. Humans have evolved over millions of years to avoid incest, and now there's no need to avoid it?

Evolution is telling us otherwise, true or not.

Growing up with someone, or living with someone who grows up from a young age has evolved to make all those involved see one-another as part of a nuclear family, not as a potential romantic interest.

This has been known to break down when people related by blood grow up apart from their relatives, or occasionally when the evolved imperatives just don't work, but even then, the disapproval of society has also evolved to prevent this.

Answer 5

Many relationships have been considered incestuous while equally close relatives have been acceptable marriage partners. For instance, cross cousins vs. parallel cousins in many societies. Or societies in which you can not marry anyone of your patriline (or matriline) no matter how distant.

Furthermore, many relationships have been considered incestuous despite there being no blood relationship, such as relationships by marriage (stepparent/stepchild), or because of wetnursing (your wetnurse's child was your milk sibling).

This shows that incest has other structuring elements to support it on top of the genetic elements.

Answer 6

Because it's friggin' gross, man!

Taboos don't need to have any underlying functional purpose, aside from social identification. Some come about for originally-practical reasons, but not all; and even those that do, like the incest taboo, easily outlast the reason for their creation. There are, for example, cultures in which it is taboo for a son-in-law to speak with his mother-in-law, and vice-versa; why? Because that's just not how things are done, even it is really freakin' inconvenient sometimes; there is no other reason for it. There are cultures in which it is taboo to ever again speak the name of someone who has died--even if their name is a really common word, thus necessitating a generation of awkward circumlocution and new coinages. Why? Because that's just not how things are done, even it is really freakin' inconvenient sometimes. And something that is genetically programmed into our brains--to avoid mating with people we grow up with--and which produces no practical inconvenience, is likely to hold on far more strongly than the random products of undirected cultural evolution.

Answer 7

Because it fails in the additional purpose given to sexual relationship/marriage: extending or gaining influence.

Very often in the past, and in some cases still today, marriage and the underlying sexual relation were used as a mean for certain families to sanction alliances and reinforce common interests.

Keeping everything in the family is long term detrimental, because who practices it stands still while all the others move forward.

Answer 8

First me secular answer, then my theological one.

Centuries on, I'm guessing probably since the enlightenment at least, of people having aversion to the idea is in my view, the largest factor. In the the past three or so centuries, monarchy based governments fell more and more out of favor, and a not uncommon feature in those governments was incest. Families like the Habsburgs did it to an insane level.

So on top of the visible, very literal insanity it caused a number of rulers (King George III literally once shook the branch of an oak tree believing he was shaking the hand of the king of Prussia), there was also a great disdain for anything associated with monarchy and old ways - so I can imagine that incest would be seen among that.

People do not sway easily. You could similarly talk about something like cannibalism - someone could write in their will (if I die in a car crash, I want you to eat me) and the idea of that sends most people into feeling really sickened, especially family members.

Personally, with my family members, I have lived my whole life seeing them in a way completely divorced from romantic love. I love them yes, but not in any real physical manner. The idea of it makes me feel very uncomfortable.

I'd further say that evolution (or God if you prefer) probably hardcoded into many of us a disdain for being intimate with people too genetically close to us.

Now, into theology. From my perspective, most who practice Judaism, Christianity, or Islam, would probably not move on this matter easily. A lot of Christians especially are extremely committed to "what does the Bible say" and if you veer too far from the intention of the texts, no matter the translation, you are going against God. I think this would be an extremely hard sell, as while I've heard some interesting arguments that homosexuality is not forbidden by the Bible, incest is far more ironclad. Leviticus lists in great detail not to have relations with your parents, children, and numerous family relations.

That would be an line that many would point to. I'm sure others will have other arguments why religion would prevent people from accepting incest, be it tradition, it being forbidden by religious authorities, etc - that I think is rather obvious of an answer.

So I will share a more specific, different kind of one. I'm a member of The Church of Jesus Christ of Latter-day Saints. To us, marriage is one of the most important decisions we undertake in this life (or the next life if there are extraneous circumstances). We believe marriage is not "till death do you part" but in fact lasts forever. Pending faithfulness on both sides, a husband and wife will be united, or sealed to each other, and any children they have for eternity.

Their children, then, upon marrying, weld a new link in this great chain - the husband and wife sealed together, the children sealed to their parents, and then those children being sealed to their own spouses. We believe that this is one of the greatest things beyond this life, that ultimate joy can only be found through the bonds of family.

Incest however, fouls this up considerably. One way to see marriage, I would say, is an act of finding someone out there, and inviting them to share in the joy my family has. In some cases it may even have saving power. Maybe their family is abusive, has problems with alcohol, or something like that. Reaching out to someone then outside of people you've known your whole life, and making them part of your life, thus can bring joy to them, and those around them (not saying necessarily that you can't marry a childhood friend or something.)

And of course, I acknowledge my aversion to incest from just longstanding western culture. Incest sullies the purity in that family chain. Of course, no family line is going to be "perfect" if one could even call it that. Divorces, fallings out between parents and children - all that happens.

But incest... incest to me feels like taking it to a whole other level. Last personal thought - it feels weird to me, because, most of the time, when two people marry, it is after they have known each other for say, maybe a few years, maybe through high school or as far back as junior high.

The thought of siblings having relations just feels disgusting to me, because if that were normalized, you'd watch two brothers at like age five wrestling with each other or something... and some might think about later on...

This in the end will be the big thing standing in the way of this. Many people who align with conservative views (on a large spectrum of stuff, not conservative in the political sense) will take great pause at all this. Normalizing incest to many would just feel extremely awful. It would confirm many people's existing feelings that society is trying to normalize too many behaviors and will not stop, even with such awful things as pedophillia. Whether this is a correct view or not is not for me to say, and I honestly can't say for sure much of the time.

I give all this, as a wide breadth of why people would push against this. I hope especially that my personal background doesnt' come across too much as opinion based - I simply wanted to provide a unique perspective on this.