Twin, Adoption, and Family Studies
Caitlin M. Jones
Rochester Institute of Technology
Adoption studies are critical in examining the relationship that exists between adopted children and both their biological and adoptive parents because they assume to separate nature and nurture. Studies have been conducted that test for the criminal behavior of the adopted-away children, if their biological parents had also been involved with criminal activity. In Iowa, the first adoption study was conducted that looked at the genetics of criminal behavior. The researchers found that as compared to the control group, the adopted individuals, which were born to incarcerated female offenders, had a higher rate of criminal convictions as adults. Therefore this evidence supports the existence of a heritable component to antisocial or criminal behavior (Tehrani & Mednick, 2000). Another study in Sweden also showed that if a biological background existed for criminality, then there was an increased risk of criminal behavior in the adopted children. In Denmark, one of the largest studies of adopted children was conducted and found similar results to the previous studies. The defining feature of the Denmark study was that the researchers found a biological component for criminal acts against property, but not for violent crimes (Joseph, 2001). Children whose biological fathers had been convicted of property crimes were more likely to engage in similar behavior, when compared to those biological fathers who had been convicted of violent crimes. According to an article by Jay Joseph (2001), who studied all of the minor and major adoption studies, the majority of researchers have found and agreed upon the non-significance of genes in violent crime. This reestablishes the findings from the studies mentioned already in that there may be a genetic component to antisocial behavior or that genes influence criminal behavior, but specifically for property offenses.
This article is an exceptional read on "nature vs. nurture." I did a research paper for psychology on nature vs. nurture. It was about twins separated at birth.
One set of twins were particularly interesting (their names escapes me at the moment) because they were separated and adopted out at birth. The families that adopted them were average families, neither family had a criminal history.
The twins ended up with almost mirroring criminal histories and both ended up on death row. They never met and were imprisoned on opposite sides of the country.
This started my fascination with nature vs. nurture.