In a move likely to renew a longstanding ethical controversy, geneticists are quietly making plans to study the DNA of Adam Lanza, 20, who killed 20 children and seven adults in Newtown, Conn. Their work will be an effort to find biological clues to extreme violence.
The researchers, at the University of Connecticut, declined to provide details. But other experts speculated that the geneticists might look for mutations that might be associated with mental illnesses and ones that might also increase the risk for violence.
They could look at all of Lanza’s genes, searching for something unusual like gene duplications or deletions or unexpected mutations, or they might determine the sequence of his entire genome, the genes and the vast regions of DNA that are not genes, in an extended search for aberrations that could determine which genes are active and how active they are.
But whatever they do, this apparently is the first time researchers will attempt a detailed study of the DNA of a mass killer.
Some researchers, like Dr. Arthur Beaudet, a professor at the Baylor College of Medicine and the chairman of its department of molecular and human genetics, applaud the effort. He believes that the acts committed by men like Lanza and the gunmen in other rampages in recent years — at Columbine High School and in Aurora, Colo., in Norway, in Tucson, Ariz., and at Virginia Tech — are so far off the charts of normal behavior that there must be genetic changes driving them.
“We can’t afford not to do this research,” Beaudet said.
Other scientists are not so sure. They worry that this research could eventually stigmatize people who have never committed a crime but who turn out to have a genetic aberration also found in a mass murderer.
Everything known about mental illness, these skeptics say, argues that there are likely to be hundreds of genes involved in extreme violent behavior, not to mention a variety of environmental influences, and that all of these factors can interact in complex and unpredictable ways.
“It is almost inconceivable that there is a common genetic factor” to be found in mass murders, said Dr. Robert Green, a geneticist and neurologist at Harvard Medical School. “I think it says more about us that we wish there was something like this. We wish there was an explanation.”
Scientists are well aware of the fraught history behind the questions of biology and violence.
In the early 20th century, claims that criminal behavior was inherited arose during the eugenics movement and led to sterilizations of mental patients and felons.
On Christmas Day in 1965, two researchers published a paper saying men with an extra Y chromosome, the chromosome that confers maleness, were “super males” and born criminals. The hypothesis was helped along by the fact that these men “fit the classic Hollywood criminal — big, awkward, thuglike and with low IQs,” said Dr. Philip Reilly, a lawyer and clinical geneticist who has studied this history.
The idea persisted for about 15 years, Reilly said, but eventually the epidemiological evidence convinced scientists that these men were no more violent than men without an extra Y chromosome.