It is an age many parents dread, the point at which the so-called 'terrible twos' strike.

For some parents the temper tantrums are short lived.

But, a new study warns, for others the melt downs could signal a darker side to their child's personality.

Experts have identified clues that can suggest whether the 'terrible twos' is just a blip, or if they are actions that are likely to escalate to aggression, stealing and bullying.

They studied 'callous-unemotional' behaviors in the toddler years that include lack of empathy, lying and little emotion in children who would likely have the worst behavior problems years later.

A new study suggests in some children the 'terrible twos' could be a sign your child will grow up to be aggressive, steal and bully others (file image)

They said these children are likely to end up bullying others despite the consequences or how the victim feels.

Dr Luke Hyde, assistant professor at the University of Michigan, and lead author of the study, said: 'These are signs for parents and doctors to watch out for, as they may signal more than just the terrible twos.'

In fact, when these behaviors are not corrected, children could get into trouble with the law later in life, he warned.

While most children grow out of the 'terrible twos' to become well adjusted, research has shown that most career criminals started their antisocial behavior during their toddler years.

Callous-unemotional behaviors are very distinct from other behavior problems, said Professor Jenae Neiderhiser, at Penn State University.

She said: 'If we can identify these kids early we may have a better chance of intervening in a child's development.'

Beyond identifying these behaviors as early signs of trouble, the researchers' work sheds light on the origins of the behaviors.

Decades of research have shown that harsh and negative parenting is linked to the development of antisocial behavior.

 Dr Hyde said: 'The challenge in this research has been knowing the true origins of these behaviors because parents both take care of their child and provide their child's genes.

'So, it's been difficult to know if we're seeing that parenting causes callous-unemotional behaviors, or is just a sign of the genes being passed to the child.'

This is the first known study to focus on the causes of early callous-unemotional behaviors.

To examine the role of nature versus nurture, the team followed 561 families in the Early Growth and Development Study - an adoption study, which documented biological mothers' history of severe antisocial behavior, as well as adoptive parent and child behaviors.

Observations of adoptive mother positive reinforcement took place when the child was 18 months.

And at 27 months researchers examined the child's behavior. 

The team found that the biological mothers' antisocial behavior predicted callous-unemotional behaviors in their children who were adopted as infants, despite having limited or no contact with them. 

In other words, the researchers concluded those behaviors were inherited.  

Researchers at Michigan, Penn State and Oregon universities found callous-unemotional behaviors, including a lack of empathy and emotion and lying, can result in a child growing up to be a criminal. They suggest these traits are inherited, running in families passed down through their genes (file image)

However, researchers found high levels of positive reinforcement by adoptive mothers helped to mitigate callous-unemotional behaviors in their adopted children.

'These findings are important because they mean that treatment programs that help parents learn to be more positive can help to stem the development of CU behaviors,' said Rebecca Waller, a U-M research fellow who contributed to the study.

The team will be following this group of children through early adolescence to determine if these behaviors still persist from toddlerhood.

'The really exciting take-home message from this study is that small, day-to-day positive interactions that parents have with their young children can make a huge difference in children's development,' said Leslie Leve, a professor at the University of Oregon who co-led the collection of the data for this study.

'Even when a child has inherited a very challenging set of behaviors, hearing 'good job' or receiving a pat on the back can help protect that child from developing serious problems stemming from their inherited difficulties.'

The study, which is supported of the National Institutes of Health and Penn State's Social Science Research Institute, is published in The American Journal of Psychiatry.

Culled from Mail Online