Geneticists have been asked to study the DNA of Adam Lanza, the Connecticut man whose shooting rampage killed 27 people, including an entire first grade class.

IS there an "evil" gene? A group of United States geneticists want to study Newtown school killer Adam Lanza's remains to find out.

The New York Times reports that a spokesperson at the University of Connecticut has confirmed the researchers' plans, but declined to provide any further details.

Adam Lanza, 20, shot his mother before driving to Sandy Hook Elementary School where he slaughtered 20 children and six adults. It was one of the United States' worst ever school shootings.

Speculation is rampant that the geneticists will look for mutations that may be linked with mental illnesses or associated with violent predispositions within Lanza's DNA.

It would be the first detailed study of the DNA of a mass murderer.

The search for an easy means of finding potentially "evil" people has a long and dubious history, most notably the pseudoscience of phrenology which claims to detect a criminal mindset through the shape of a skull.

The eugenics movement of a century ago insisted "evil" behaviour was inherited, leading to the sterilisation of criminals and mental patients.

However, Dr Arthur Beaudet, a genetics professor at the Baylor College of Medicine in Texas, told the newspaper: "We can't afford not to do this research".

He said he believed the behaviour of gunmen - including the Columbine High School and Norway mass killings - was so extreme that there "must be" a genetic basis to their actions.

Other scientists expressed the fear that such research would result in the arbitrary classification and stigmatisation of people who have never committed a crime, but produced a positive result on a genetic test.

"It is almost inconceivable that there is a common genetic factor," Harvard geneticist Dr Robert C. Green said.

"I think it says more about us that we wish there was something like this. We wish there was an explanation."

But others insist the science of genetics has come a long way in recent years, reducing the risk of racial or minority biases.

Duke University neurobiologist Pate Skene said powerful new DNA sequencing systems could easily identify the genetic roots of a condition.

But he was less certain of the value of any such data.

"If we know someone has a 2 per cent chance or a 10 per cent chance or a 20 per cent chance of violent behavior, what would you do with that person?" Skene said.

"They have not been convicted of anything - have not done anything wrong."