You Are Sexually Attracted to Your Parents, and Yourself

Study: People are drawn to others who resemble their kin or themselves.

ByABC News
July 29, 2010, 11:00 AM

July 29, 2010— -- It's not an excuse, but there may be a biological reason that jail-bound Aimee Sword was sexually attracted to the teenage son she gave up for adoption.

In a series of experiments where subjects viewed photographs of their opposite-sex parent or a photo morphed with their own face, researchers found that people are turned on by photographs of people who resemble their close genetic counterparts.

"People appear to be drawn to others who resemble their kin or themselves," said psychologist R. Chris Fraley of the University of Illinois, lead author of the study published July 20 in Personality and Social Psychology Bulletin. "It is possible, therefore, as Freud suggested, that incest taboos exist to counter this primitive tendency."

The debate about whether aversions against incest stem from a cultural adaptation to suppress biological urge or a psychological adaptation that evolved by natural selection dates back to the early 1900s.

Psychoanalyst Sigmund Freud proposed the former explanation, and sociologist Edward Westermarck proposed the latter, arguing that there is a critical period while people are growing up during which if they are raised with someone they won't find them attractive.

In recent years, Fraley says, contemporary scholars have concluded that Westermarck was right, and Freud was wrong. But based on his study, Fraley argues that the debate may have been settled prematurely.

"There is evidence on both sides now," said psychologist David Schmitt from Bradley University. "There is some reason to think that there is something to Westermarck, that there is a critical period, but it may also be that we find and trust and align ourselves with people who have more common alleles."

In the first experiment, people were shown a series of faces of strangers and asked to rank their sexual attractiveness.

Before each of the faces were shown, half the subjects were subliminally exposed to photographs of their opposite-sex parent, by flashing the images so quickly that they couldn't be processed consciously. The other half of the participants was shown photos of unrelated parents.