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Genetic sexual attraction


Genetic sexual attraction (GSA) is a contrived term for an overwhelming sexual attraction that may develop between close blood relatives who first meet as adults. .

The term was coined in the US in the late 1980s by Barbara Gonyo, the founder of Truth Seekers In Adoption, a Chicago-based support group for adoptees and their new-found relatives.

People tend to select mates who are like themselves, which is known as assortative mating. This holds both for physical appearances and mental traits. People commonly rank faces similar to their own as more attractive, trustworthy, etc. than average. However, Bereczkei (2004) attributes this in part to childhood imprinting on the opposite-sex parent. As for mental traits, one study found a correlation of 0.403 between husbands and wives, with husbands averaging about 2 IQ points higher. The study also reported a correlation of 0.233 for extraversion and 0.235 for inconsistency (using Eysenck's Personality Inventory). A review of many previous studies found these numbers to be quite common.

Heredity produces substantial physical and mental similarity between close relatives. Shared interests and personality traits are commonly considered desirable in a mate. The heritability of these qualities is a matter of debate but estimates are that IQ is about 80% heritable, and the big five personality factors are about 50% heritable. These data are for adults in Western countries.

For the above reasons, genetic sexual attraction is presumed to occur as a consequence of genetic relatives meeting as adults, typically as a consequence of adoption. Although this is a rare consequence of adoptive reunions, the large number of adoptive reunions in recent years means that a larger number of people are affected. If a sexual relationship is entered, it is known as incest.

GSA is rare between people raised together in early childhood due to a reverse sexual imprinting known as the Westermarck effect, which desensitizes them to later close sexual attraction. It is hypothesized that this effect evolved to prevent inbreeding.


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