Frequently Asked Question: How Common is Incest?

The short answer: Nobody knows for sure, but it appears to be common enough that you know someone who has been involved, whether you know it or not. If you have been, are, or want to be involved, you are not alone and it doesn’t make you bad or sick. You’re in the company of royals and peasants, urban dwellers and rural folk, the wealthy and the poor throughout history. Regardless, rights are not reserved for the majority.

This answer is addressing consensual incest, in which I include, in addition to adults, minors who four years or less apart in age when force or coercion are not used. This is what I call “consanguinamory” or consanguineous sex. This answer is not about child molestation, sexual assault, or rape.



The question is asked various ways:

How common is consensual incest?
How common in consanguinamory?
How common is sibling sex?
How common is family sex?

I will also address:

How common are dreams of incest?
How common are incest fantasies?
How common are thoughts of incest?

I’ve already made it clear I’m talking about consensual sex. But there’s another part of the definition of incest that needs to be determined: what relations are considered incestuous ones?

If we include first cousins, then incest is very common. It some cultures, marriages between first cousins are very common. About half of US states will marry first cousins (currently, most of those states don’t marry same-sex couples, so mostly we are talking about heterosexual relationships).

Including step-relations (stepsiblings, for example) or adopted relations, as some anti-incest laws do, then again, incest is very common.

But even if we only include half or full-blooded siblings, parents and their adult children, grandparents and their adult grandchildren, and aunt/uncles and nieces/nephews, incest is common enough that everyone knows someone who has been involved in incest, especially if we include people experiencing Genetic Sexual Attraction (the meaning of which includes the fact that they were not raised with or by each other).

As I said in the short answer, nobody knows for sure. Ridiculous laws against consensual incest along with other forms of discrimination, prejudice, ignorance, bullying, and ridicule don’t exactly foster an atmosphere of open and honest discussion or reliable research. If we rely on such things as…

personal responses to surveys…which are likely to have underreporting even if anonymous

DNA tests…which are not performed on everyone, nor always checked for indications of consanguinity

criminal cases…which only involve a very small minority of relationships

family records and oral history…which are likely to hide incestuous ancestry even if it was known, which it often wasn’t

…we’re still not going to know about everything. Still, what we have seen indicates that a sizable minority of the population has participated in consanguinamory, and many more have thought about or fantasized about it. If you have entertained thoughts about having a threesome with twins or other siblings, or with a parent and their adult child, you have thought about incest. Internet searches and traffic, online discussion and chat areas, and erotica (see Literotica.com and the "Taboo" movie series) or adult media publication and usage indicate a high level of interest. Histories, biographies, mythologies, and fiction of all kinds, in movies and books and more, from years past through today also contain tales of consensual incest.

Youthful crushes, infatuations, fantasies, and exploration may just be a passing phase, or may develop into a lifelong spousal-style relationship, or fall anywhere between those two ends of the spectrum. While many children play doctor or games that lead to some experimentation, some people don’t have their first brush with consanguinamory until well into their adult years; even as elderly widows and widowers.

As far as incestuous dreams, it should be noted that sex or sexual attraction in dreams is sometimes representative of feeling close to someone or wanting to be closer or show love in some way. It isn’t always an indication of an actual sexual attraction, but sometimes it is.

Studies indicate that most people are attracted to people who look like themselves, which obviously includes close biological relatives more than anyone else. However, when any two people are raised together in the same family or group home, or one raises the other in such close quarters, related or not, something called the Westermarck Effect may suppress attraction to each other. This effect isn’t present in everyone, or isn’t present strongly enough to suppress attraction or curiosity in everyone. Also, close biological relatives who were not raised together (or one wasn’t raised by the other) wouldn’t experience this effect. On the contrary, the extremely powerful effect of Genetic Sexual Attraction is present in up to half of all reunions/introductions of post-pubescent close biological relatives (after adjusting for sexual orientation). With divorces, break-ups, one-night stands or other relationships in which parents their children or siblings may be separated, adoption, and egg, sperm, and embryo donations, this is becoming an increasing phenomenon in our highly mobile world.

Many people who have experienced Genetic Sexual Attraction, even those who are in lasting, happy consanguinamorous relationships together would have expressed disapproval or discomfort at the idea of consanguinamory before they experienced GSA. But just because one person is disgusted or insists they would never do such a thing doesn’t make it wrong for someone else, nor does it change the fact that does happen. As for consanguinamory between family members raised together or raised by each other, the convenience of proximity and privacy, and the existing foundations of trust and love may foster curious, fleeting exploration or deep and abiding passion.

None of this is to say that any one person should pursue a consanguinamorous relationship with another. Not everyone is right for everyone else at any given time in life. I have my own advice about making a decision about a possible relationship.

If someone in your family or one of your friends is in a consanguinamorous relationship and you are concerned, please read this.