Children who are overvalued by their parents are more likely to grow up to be selfish little narcissists, scientists said Monday.

In a study published in the U.S. journal Proceedings of the National Academy of Sciences, researchers found children who were described by their parents as "more special than other children" and as kids who "deserve something extra in life" tended to score higher on narcissism tests.

"Children believe it when their parents tell them that they are more special than others," study author Brad Bushman, professor of communication and psychology at the Ohio State University, said in a statement. "That may not be good for them or for society."

Lead author Eddie Brummelman, a postdoctoral researcher at the University of Amsterdam in the Netherlands said parents who overvalue their children may think that will help boost their self- esteem but the results are always the opposite.

"Rather than raising self-esteem, overvaluing practices may inadvertently raise levels of narcissism," Brummelman said.

Narcissism can induce aggressive behaviors and an increased risk of mental health problems. Two opposing theories of narcissistic origins exist: one proposes that children develop narcissistic traits when their parents overvalue them, while the other proposes that narcissistic traits emerge in children whose parents fail to express warmth toward them.

The new study was based on four surveys of 565 children in the Netherlands who were seven to 11 years old when the study began, and their parents, each six months apart.