Is Adult Incest Wrong?

An version of this article was printed in Humanism Ireland, March-April, Vol. 151 (2015) 

Incest is something most people find morally objectionable and it's one of the most common of all cultural taboos. The British Medical Association’s Complete Family Health Encyclopaedia (1990) defines incest as “intercourse between close relatives,” that usually includes “intercourse with a parent, a son or daughter, a brother or sister, an uncle or aunt, a nephew or niece, a grandparent or grandchild.” The Oxford English Dictionary’s definition is a little broader: it doesn’t confine incest to just intercourse, but to “sexual relations between people classified as being too closely related to marry each other.”   

Most countries have some kind of law against incest—though consensual adult incest is not a crime in France, Spain, Russia the Netherlands, and a host of countries in South America. In England and Wales, however, the Sexual Offences Act 2003 makes it an offence for someone to intentionally sexually penetrate a blood relative and it can carry a punishment of up to two years in prison.  Incest is also illegal in the Republic of Ireland under the Punishment of Incest Act 1908, and the maximum prison term for males was increased to life imprisonment by the Criminal Law (Incest Proceedings) Act, 1995. 

At the moment there’s a growing debate in Germany over the taboo and just recently the German Ethics Council (Deutscher Ethikrat) has called for an end to the criminalisation of consensual incest between siblings. The Council’s deliberation came after examining the case of a sister and brother who have four children together.  According to The Independent, the man, who was adopted when he was just an infant, met his sister in his 20s, and “was convicted of incest in 2008 and spent three years in prison, failing an appeal to the Federal Constitutional Court in 2008 and to the European Court of Human Rights over his rights to a family life in 2012.” In their statement, the Council said “the fundamental right of adult siblings to sexual self-determination has more weight in such cases than the abstract protection of the family.” It alluded to the fact that in every other set of circumstances voluntary sexual relationships between people capable of self-determination are not forbidden. The Council argues that there’s a need for a clear and convincing reason why Germany’s criminal code should concern itself with incestuous sexual relations between consenting adult siblings, and not other forms of consenting adult relations.   

Are the German Ethics Council right to say consensual sexual relations between siblings should be decriminalised? Is consensual incest ethically defensible? With the aim of obtaining a clearer understanding of the issue, let us consider some of the common arguments that are often used against the permissibility of adult incest.     

 

    

It’s Unnatural

It’s sometimes claimed that incest is unnatural and for this reason it should be considered wrong.  But how are we to determine if something is ‘natural’ or ‘unnatural’? Incest may indeed be rare, but does that make it unnatural?  And, moreover, even if we say it’s unnatural, what moral relevance does this make? Many diseases and catastrophes (like earthquakes, volcanic eruptions, and hurricanes) are considered natural, but that doesn’t make them good. Human violence and rape, arguably, are products of natural selection, but that also doesn’t necessarily make them good. Likewise, there are many things we usually consider unnatural, like medicine, rail transport, and anaesthesia, but not many consider them as bad.  For this reason, if we say incest is immoral merely because it’s unnatural, this particular argument doesn’t work either.  

Genetics Argument

Probably the most common argument against incest is that inbreeding increases the risk of genetic disabilities among offspring. There are problems with this viewpoint though. Firstly, the concern would only be enough to condemn vaginal intercourse between blood relatives who are fertile; it wouldn’t deny other forms of sexual intimacy between blood relatives or any form of sexual intimacy between non-blood relatives. Secondly, if we’re truly concerned about genetic disability, we should also consider not allowing anyone to have sex who has the potential to pass on defective genes to their offspring. Although I doubt there are many who would be in favour of banning the reproduction of those with hereditary diseases.

Indeed, it’s worth noting that with respect to Huntington’s disease—a distressing, impairing brain disorder—if one parent has it, there’s a 50 percent chance any child he has will also be born with the fatal disorder. In regard to the risk of cystic fibrosis, if both parents are carriers of the gene, there’s a one in four chance any child they will have will be born with the condition. If we don’t punish those carrying defective genes from having children, why then should we punish incestuous partners? If we’re not prepared to prevent carriers of congenital disorders from having children—or, for that matter, having sex—then it seems quite arbitrary and discriminatory to only punish incestuous partners.     

A possible response might be that it’s unrealistic and perhaps unfair to commit those who carry defective genes to a lifetime of abstinence and to deny them having their own offspring. These are not legitimate reasons for incestuous partners however, since it’s possible for them to have healthy offspring with someone unrelated; those carrying defective genes that could be passed on, after all, don’t have this option. For this reason, it’s not arbitrary or discriminatory, it could be argued, to only punish incestuous couples, and not those with hereditary diseases. To be sure, there are some differences between the two cases, but I don’t think it there’s enough here to claim one instance is ethically acceptable and the other is not.

Besides, advances in gene therapy have significantly decreased the risk of congenital diseases emerging in the foetus, as well as parental screening to allow doctors to test for inherited diseases in the blood, amniotic fluid, or placenta of the womb during the early stages of pregnancy. What’s more, pre-implantation genetic diagnosis allows doctors to screen embryos for inherited defects before implantation even takes place.  These various technologies are commonly used in cases of regular congenital defects; I see no reason why they could not also be extended to include cases of incest.  

Furthermore, if we give some thought to a problem in philosophy, known as the ‘non-identity-problem,’ it’s not clear that a child born as a result of an incestuous relationship is harmed, since the only other possibility for her would be not to exist. Even if the child is born with a genetic condition, and assuming she can still live a worthwhile life, it seems we cannot say her parent’s activity have harmed her, as there wasn’t any other way she could have come into existence. Maybe, in this way, it doesn’t make sense to blame the parents for her having to live with a genetic condition, as it wouldn’t be possible for her to exist without it.

Effects on Families

It’s often said that incest should be prohibited because it threatens familial stability. Family members involved in a relationship, so the argument goes, would be an emotionally traumatic experience for other members of the family and it would result in rivalries and jealousies within the family unit. Yet, it’s not always the case that incest would undermine the family. As we know from the case in Germany, for instance, it was the authorities that separated the family and took custody of the children. The laws against adult incest, in this case, actually worked against the notion of familial stability.

Rivalries, jealousies, and tense relationships certainly can be harmful to the solidarity of the family, but family disputes and rivalries also happen for several other reasons; why, then, should we single out incest? In addition, this line of thought against adult incest isn’t relevant when rivalries and jealousies are not factors. Interestingly, a similar kind of criticism is sometimes used against the permissibility of inter-denominational, inter-racial, and homosexual relationships, as they’ve also the potential, in similar ways, to undermine the family unit. But if we’re not prepared to accept the criticism in opposition to these types of relationships, then it doesn’t seem like we can use it in the case of adult incest either. Indeed, it may well be the case that in some instances the most responsible action would be for relatives to suppress any sexual desires, if an incestuous relationship was likely to lead to familial disintegration. But notice that once we accept this, we will also have to accept that, as a matter of consistency, there could be other instances—such as inter-denominational, inter-racial, and homosexual relationships—where suppressing love is the most responsible thing to do in order to preserve familial stability.

Another argument variously expressed is that the problem with incest is that there would be a great power imbalance between older relatives and younger members of the family that need protection from psychological damage, domination, manipulation and abuse. But as the legal scholar Vera Bergelson points out, this kind of argument is both overbroad and redundant. It’s overbroad in the sense that it applies to cases where power dynamics, abuse, or exploitation do not exist. (Speaking of which, we don’t prohibit non-incestuous adult relationships, merely because one partner is older, richer, or has more social status than the other). The argument is also redundant as there are already statutes directed at child abuse and statutory rape on one hand, and sexual exploitation or violence, irrespective of the age of the victim, on the other hand. The sexual acts between relations here would be immoral not because they are incestuous, but because they would amount to rape, violence or exploitation; we already regard such behaviour as wrong, independent of whether or not incest occurred.  

Societal effects

Another objection is that there would be the societal harm that would result from increased amounts of inbreeding. It would have an impact on genetic diversity by bringing about a larger amount of genetic disease and abnormalities in society. This might be a fair objection if there was good reason to assume the decriminalisation of adult incest would lead to a significant rise of inbreeding. But as we know, there are already a small number of countries that currently don’t have adult incest laws, and we’ve no reason to believe there are significant instances of inbreeding in these countries. There’s also evidence to suggest the practice will never become widespread: various studies have shown that people who live together in close proximity during early life become desensitised to future sexual attraction. In all, it’s very unlikely that cases of incest would become widespread if it were legally permissible.

A prejudice?

From the arguments I’ve examined above, none seem to give us a strong reason to say that adult incest is obviously wrong. There may be some other convincing ones that I’ve not contemplated, but I suspect most people consider incest wrong because they have a strong intuitive sense of revulsion and disgust towards it. The very idea of it instinctively produces a strong ‘yuck’ reaction. But, as I’ve argued in an earlier post, we should be sceptical about relying too much on intuitions when it comes to moral evaluation.  And, furthermore, when we recall that feelings of disgust and repugnance were once used, politically and socially, against racial minorities, homosexuals and other unfavourable groups, it suggests, also, that these emotions are unreliable when assessing the ethics of adult incest.

If this is the case, then perhaps a lot of the opposition to it is based on an irrational prejudice—a sense of moral revulsion against a harmless taboo. In fact, the philosopher Jeffrey Sebo has argued that academic scholarship and the media have largely helped to propagate the repulsive image. With abortion, for example, some of the common grounds in favour of it usually include rape, foetal abnormality and incest. Why, Sebo asks, is an incest clause necessary for the permissibility of abortion? In the case of a father who has raped and impregnated his daughter, a rape clause would be adequate grounds for it; in cases of congenital disorders, abortion would be permissible if the foetus showed signs of genetic damage. However the incest factor, Sebo claims, is irrelevant to the permissibility of abortion. If an abortion rights group included an interracial pregnancy clause as sufficient grounds for abortion, there would, rightly, be a strong suspicion of racial prejudice.

In the same manner, gay marriage proponents often get irritated and offended when opponents say “if we allow gay marriage, why not incest?" Opponents probably are invoking homophobia when they express statements like this to win arguments; but perhaps proponents, who are offended and insulted by the comparison, but without a persuasive reason-based argument against adult incest, are also invoking a prejudice when expressing such a point of view.  In the absence of such an objection, it seems the German Ethics Council were correct to say we’ve no right to prevent consenting adults from engaging in sexual activity just because most people in society  consider it disgusting.