Science of Sex: Genetic Sexual Attraction

July 15th, 2017

Welcome to the fifth installment in a new feature on Of Sex and LoveScience of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.


science of sex genetic sexual attraction

Genetical sexual attraction is the phenomenon where two people who are biologically related but first meet in their adulthood as strangers and experience sexual attraction to one another. Genital sexual attraction, or GSA, can occur between siblings or a child and a parent.

Adoption is the main environment of GSA, and changing laws allowed many adopted people seek out their biological families, which can lead to one or both parties experiencing genetic sexual attraction. The attraction comes on suddenly and strongly and the senses of hearing, touch and smell play a significant role. To many, the term “attraction” isn’t strong enough. It’s an obsession or an addiction with the accompanying compulsions and inability to stop thinking about their attraction.

Cause of Genetic Sexual Attraction

Part of the draw might be meeting someone who shares similar personality traits and appearance, a result of genetics. This can lead people to a frenzied state much like new relationship energy — except they’re related. There is also an argument for an attraction based on similar genes, specifically having similar phenotypes (traits an individual of a species has based on gene and environmental interaction), which would obviously be the case for two people who are related.

People who experience genetic sexual attraction often feel confused and shame as they grapple attraction for their family members. People who try to deny their thoughts and feelings may wind up even more entrenched due to the ironic process theory (your brain must keep thinking about any subject you’re trying to avoid to monitor whether it’s thinking about it). In some instances, attraction occurs for only one of the people, and that person may pursue the object of their desire compulsively.

When the attraction is equal, the parties may engage in sexual activities or intercourse. GSA sex seems to occur most frequently between siblings. Some couples have been arrested and tried for incestuous relationships. These laws strive to reduce offspring from an incestuous relationship because those children are likely to suffer severe birth defects or mental disabilities.

Some people who have developed romantic relationships with their biological family members are fighting for the right to marry the people that they have only known as an adult – and never as a family member.

There are reported cases of GSA among adults who only discovered that they were related to their romantic/sexual partners after developing a romantic/sexual relationship.

Incest Taboo

It might be more telling to understand where the taboo incest comes one. It may be due to the Westermarck effect,  also known as reverse sexual imprinting, which endeavors to explain the incest taboo by showing that people develop a sort of sexual immunity to their family members after living with or near them during their developing years.

Dr. Maurice Greenberg performed a study in 1992 and discovered that many people who experienced genetic sexual attraction to a biological family member shared typical disgust toward incestuous relationships with their adopted families, which led him to differentiate between incest and GSA.

However, we also know that sexual imprinting (in which someone chooses a mate similar to a parent) exists and can occur in adoptive families as well as biological ones.

Frequency of GSA

One study suggests that it happens in as many of half of those instances of adult family members meeting for the first time while another study found that every informant had experienced genetic sexual attraction and one-third of those people had engaged in sex with a bio family member.

A few professionals and communities have developed to provide support to those people who might be struggling, either because they’re experiencing unwanted GSA or because they’ve chosen a relationship with a biological family member.

One notable name is Barbara Gonyo, the woman who first coined the term genetic sexual attraction after herself experiencing it toward her son. While he didn’t return the attract and Gonyo eventually moved on from her obsession and now provides counseling services to others like her.

Like any attraction, the flame can wither and die. Barbara has been able to overcome the feelings of attraction to her son, who is now married.

Further Reading